Image capture device with automatic focusing function

ABSTRACT

In a digital camera, a focus lens is moved at a low speed between a timing at which a shutter key is half pressed and a timing at which the shutter key is fully pressed to detect a focused position. When the shutter key is fully pressed by a user before the focus lens reaches a focused position, the focus lens is moved at a higher speed than that of a case in which the shutter key is half pressed, and a focused position is detected. Thereby, even when the shutter key is fully pressed by a user before the focus lens reaches the focused position, the digital camera can realize focusing with less delay in capturing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromprior Japanese Patent Applications No. 2005-021767, filed Jan. 28, 2005;No. 2005-040200, filed Feb. 17, 2005; and No. 2005-332394, filed Nov.17, 2005, the entire contents of all of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an image capture device which can beused for a digital camera, and is provided with an automatic-focusingfunction and to a method for automatic-focusing control.

2. Description of the Related Art

Conventionally, a digital still camera (hereinafter, called a digitalcamera) provided with an automatic-focusing function according to anautomatic focusing (AF) method of a contrast detection type has beenknown.

The digital camera provided with an automatic-focusing function extractsa high frequency component by using a high pass filter after necessarypreprocessing of image data for a subject image formed with a lens unitwhen a shutter button is half pressed. Then, image formation can berealized at the best focus position by driving the lens unit andadjusting a focus position in such a way that the high frequencycomponent of the whole data is a maximum value.

According to a method for detecting a focus position in such a way thatthe high frequency component is the maximum value, it is determined, bythe above-described processing of the image data at a necessary intervalwhile the focus position is changed from infinite distance to this sideby driving the lens unit, whether or not the high frequency component isthe maximum value. Then, the image data of the subject image isrecorded, wherein the subject image has been captured at the best focusposition by finally driving the lens unit to a focus position at whichthe high frequency component is the maximum value, and by full-pressingof the shutter button under a state that the high frequency component isthe maximum value.

Even when the shutter button is fully pressed at one stroke, ahalf-pressed state is always passed to start focusing adjustment, thesubject image is captured at the best focus position, and the image datafor the subject image is recorded.

However, a conventional digital camera provided with anautomatic-focusing function according to an AF method of a contrastdetection type requires image data processing and driving control of alens unit for determining an appropriate lens position at which asubject is in focus, as described above. Accordingly, there have beenproblems: a problem that the shutter is not released at the right momentbecause there is necessary time between time at which a camera usercatches a subject in a finder and time at which the subject is in focusand a shutter button is fully pressed for image forming; and a problemthat a subject image with some lag between a full-pressing point and apoint at which an image captured by the camera user might be obtained isrecorded even when the shutter button is fully pressed at one strokebecause the recorded image is an image which has been formed when theimage is in the best focus.

In order to solve the above-described problems, there has been disclosedan image capture device (refer to, for example, Jpn. Pat. Appln. KOKAIPublication No. 2004-085697 (Patent Document 1)) for capturing a subjectimage in a state in which the shutter is released at the right momentand the time lag is eliminated, thereby recording the subject image.According to the above image capture device, it is discriminated, whenan image is captured, whether an interrupt processing flag is ON or OFF.When a shutter button is “half pressed”, the interrupt processing flagis set to be ON, and it is determined whether or not there is a “fullypressed” signal from the shutter button. When the shutter button is“fully pressed” at one stroke, the determination is assumed to be YES.Accordingly, a charge coupled device (CCD) outputs image data forexposure, and the image data for exposure is separated to a luminancesignal and a color difference signal in a color processor. A centralprocessing unit (CPU) stores the separated luminance signal and colordifference signal into a RAM. Consequently, image data, which isobtained when the shutter button is fully pressed before focusing iscompleted, is configured to be stored in the RAM.

Moreover, there is an advantage that time for detecting a focusedposition can be reduced in driving control of a lens unit when thedriving speed of the focus lens is increased, but there is adisadvantage that it is difficult to accurately stop the focus lens at afocused position. There has been a technology (refer to, for example,Jpn. Pat. Appln. KOKAI Publication No. 2002-287012 (Patent Document 2))which brings the above-described advantage and the above-describeddisadvantage into harmony with each other, based on the above-describedviewpoint, by changing the driving speed of the focus lens according tosituations and by detecting the focused position.

According to the patent document 2, when a release button (shutter key)is half pressed, low-speed driving of the focus lens is started, andsubsequently, a difference between the current position of the focuslens and a focused position is measured. If the measured value issmaller than a predetermined value, the focus lens is driven at a lowspeed with no change in the speed. If the measured value is smaller thanthe predetermined value, time for detecting the focused position isshortened by driving the focus lens at a high speed.

BRIEF SUMMARY OF THE INVENTION

An object of the present invention is to provide an image capture deviceand a control method for automatic focusing, by which an image with goodfocusing accuracy can be obtained with right-time firing of the shutterand without generating time lag.

According to an embodiment of the present invention, an image capturedevice comprises:

automatic-focusing means for comparing contrast values of capturedimages which are sequentially obtained through an image capture elementwhile moving a focus lens and for detecting a focused lens position ofthe focus lens based on results of comparisons;

a shutter button which is able to be half pressed and fully pressed;

first determining means for determining whether or not the shutterbutton is half pressed;

second determining means for determining whether or not the shutterbutton is fully pressed;

first automatic-focus control means for, when the first determiningmeans determines that the shutter button is half pressed, executing afirst automatic-focusing processing by using the automatic-focusingmeans; and

second automatic-focus control means for, when the second determiningmeans determines that the shutter button is fully pressed, executing asecond automatic-focusing processing with higher processing speed thanthat of the first automatic-focusing processing by using theautomatic-focusing means.

According to an embodiment of the present invention, an image capturedevice comprises:

capturing means for capturing a subject image;

automatic exposure means for setting an appropriate exposure value forthe capturing means;

a shutter button which is able to be half pressed and fully pressed;

first determining means for determining whether or not the shutterbutton is half pressed;

second determining means for determining whether or not the shutterbutton is fully pressed;

first automatic-exposure control means for, when the first determiningmeans determines that the shutter button is half pressed, controllingthe automatic exposure means to execute a first automatic-exposureprocessing; and

second automatic-exposure control means for, when the second determiningmeans determines that the shutter button is fully pressed, controllingthe automatic exposure means to execute a second automatic-exposureprocessing which is simpler than the first automatic-exposureprocessing.

According to an embodiment of the present invention, an image capturedevice comprises:

capturing means for capturing a subject image;

automatic white balance means for setting an appropriate white balancevalue for the capturing means;

a shutter button which is able to be half pressed and fully pressed;

first determining means for determining whether or not the shutterbutton is half pressed;

second determining means for determining whether or not the shutterbutton is fully pressed;

first automatic white balance control means for, when the firstdetermining means determines that the shutter button is half pressed,controlling the automatic white balance means to execute a firstautomatic white balance processing; and

second automatic white balance control means for, when the seconddetermining means determines that the shutter button is fully pressed,controlling the automatic white balance means to execute a secondautomatic white balance processing which is simpler than the firstautomatic white balance processing.

According to an embodiment of the present invention, an image capturedevice comprises:

capturing means for capturing a subject image;

stroboscopic light charging means for executing stroboscopic lightcharging for a stroboscopic-light unit;

stroboscopic light-emitting means for emitting a stroboscopic light byusing the stroboscopic-light unit charged by the stroboscopic lightcharging means;

a shutter button;

first determining means for determining whether or not the shutterbutton is operated; and

capturing control means for, when the first determining means determinesthat the shutter button is operated, controlling the capturing means toexecute capturing regardless of whether or not a stroboscopic lightcharging is executed by the stroboscopic light charging means.

According to an embodiment of the present invention, an image capturedevice comprises:

capturing means for capturing a subject image;

automatic exposure means for setting an appropriate exposure value forthe capturing means;

a shutter button;

first determining means for determining whether or not the shutterbutton is operated; and

capturing control means for, when the first determining means determinesthat the shutter button is operated, controlling the capturing means toexecute capturing regardless of whether or not automatic-exposureprocessing is executed by the automatic exposure means.

According to an embodiment of the present invention, an image capturedevice comprises:

capturing means for capturing a subject image;

automatic white balance means for setting an appropriate white balancevalue for the capturing means;

a shutter button;

first determining means for determining whether or not the shutterbutton is operated; and

capturing control means for, when the first determining means determinesthat the shutter button is operated, controlling the capturing means toexecute capturing, regardless of whether or not automatic white balanceprocessing is executed by the automatic white balance means.

According to an embodiment of the present invention, an image capturemethod comprises:

determining whether or not a shutter button, which is able to be halfpressed and fully pressed, is fully pressed; and

executing a second automatic-focusing processing when it is determinedthat the shutter button is fully pressed, a processing speed of thesecond automatic-focusing processing being faster than a processingspeed of a first automatic-focusing processing which is to be executedwhen it is determined that the shutter button is half pressed.

According to an embodiment of the present invention, an article ofmanufacture comprising a computer usable medium having computer readableprogram code means embodied therein, the computer readable program codemeans comprises:

computer readable program code means for causing a computer to determinewhether or not a shutter button, which is able to be half pressed andfully pressed, is half pressed;

computer readable program code means for causing a computer to determinewhether or not the shutter button is fully pressed;

computer readable program code means for causing a computer to execute afirst automatic-focusing processing when it is determined that theshutter button is half pressed;

computer readable program code means for causing a computer to execute asecond automatic-focusing processing when it is determined that theshutter button is fully pressed, a processing speed of the secondautomatic-focusing processing being faster than a processing speed ofthe first automatic-focusing processing.

Additional objects and advantages of the present invention will be setforth in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the present invention.

The objects and advantages of the present invention may be realized andobtained by means of the instrumentalities and combinations particularlypointed out hereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the presentinvention and, together with the general description given above and thedetailed description of the embodiments given below, serve to explainthe principles of the present invention in which:

FIG. 1 is a block diagram showing a configuration example of a digitalcamera according to first and second embodiments of the presentinvention;

FIG. 2 is a block diagram showing a configuration example of an AFcontrol unit shown in FIG. 1;

FIG. 3 is a flowchart showing the content of concrete operations for thedigital camera according to the first embodiment;

FIG. 4 is a graph showing a relation between positions of a focus lensand AF evaluation values;

FIG. 5 is a flowchart showing an outline of AF operations at switchingbetween AF processing in low-speed mode and AF processing in high-speedmode;

FIG. 6 is a view explaining the first embodiment, and five modifiedexamples of the first embodiment;

FIG. 7 is a view showing combination examples of AF processing inlow-speed mode and AF processing in high-speed mode;

FIGS. 8A and 8B are views each explaining a method for searching a focuspoint according to the third modified example of the first embodiment;

FIG. 9 is a flowchart showing an outline of AF operations of AFprocessing in low-speed mode according to the third modified example ofthe first embodiment;

FIG. 10 is a flowchart showing an outline of AF operations in high-speedmode according to the third modified example of the first embodiment;

FIG. 11 is a view explaining a focus-lens moving range according to thefifth modified example of the first embodiment;

FIG. 12 is a flowchart showing the content of concrete operations forthe digital camera according to the second embodiment;

FIGS. 13A and 13B are views each showing a relation between thepositions of the focus lens and the AF evaluation values in a case inwhich AF processing is switched to AF processing in high-speed modeduring AF processing in low-speed according to the second embodiment;

FIGS. 14A, 14B, and 14C are views each showing an appearance of oneexample of a digital camera according to third and fourth embodiments ofthe present invention;

FIG. 15 is a view showing one example of an electric circuitconfiguration for the digital camera shown in FIGS. 14A to 14C;

FIG. 16 is a flowchart showing one example of one-stroke determinationof the shutter key and capturing operations in the digital cameraaccording to the third embodiment;

FIGS. 17A and 17B are views each explaining a corresponding table forsimple AF processing, in which the zoom values and the search intervalsare correlated with one another;

FIG. 18 is a flowchart showing one example of one-stroke determinationof the shutter key and capturing operations in the digital cameraaccording to the third embodiment when a forced stroboscopiclight-emitting mode (or automatic flash mode) is selected;

FIG. 19 is a flowchart showing a modified example of one-strokedetermination of the shutter key and capturing operations in the digitalcamera according to the third embodiment;

FIG. 20 is a flowchart showing one example of one-stroke determinationof the shutter key and capturing operations in the digital cameraaccording to the fourth embodiment; and

FIG. 21 is a flowchart showing a modified example of one-strokedetermination of the shutter key and capturing operations in the digitalcamera according to the fourth embodiment.

DETAILED DESCRIPTION OF THE INVENTION

An embodiment of the present invention will now be described withreference to the accompanying drawings. Configurations of a digitalcamera 1 according to first and second embodiments of the invention willbe first explained.

First Embodiment

As shown in FIG. 1, the digital camera 1 is provided with an automaticfocus-adjusting function (AF function), and comprises an optical lenssystem 2; an image capture element 3; an analog-digital (A/D) converter4; an image processing unit 5; a release operation unit 6; a cameraoperation unit 7; a display device 8; a memory unit 9; a control unit10; a lens driving motor unit 11; and an AF control unit 12.

The optical lens system 2 comprises an image capture lens, a focus lensfor focusing, a stop mechanism for adjusting an amount of light incidenton the image capture element 3, and the like. An optical image of asubject (subject image) focused through the optical lens system 2 isformed on the image capture element 3.

The image capture element 3 is, for example, a CCD, and accumulates asubject image focused through the optical lens system 2 after convertingthe image into charges with a large capacity corresponding to thebrightness of the image. Then, the image capture element 3 outputs theaccumulated charges as an image signal (analog signal) by scanning drivewith a timing generator and a vertical (V) driver which are not shown.

The image signal output from the image capture element 3 is amplifiedthrough an automatic gain control (AGC) amplifier (not shown) afternoises on the signal are removed in a correlation double sampling (CDS)circuit (not shown), and the signal is converted into a digital signalin the analog-digital (A/D) converter 4.

The image processing unit 5 comprises a color processing circuit, adirect memory access (DMA) controller, and the like (not shown). Theimage processing unit 5 performs color processing of the image signal indigital form, which is supplied from the A/D converter 4, in the colorprocessing circuit to generate a luminance signal Y, color differencesignals Cb, and Cr.

Subsequently, the image processing unit 5 performs DMA transfer of theluminance signal Y and the color difference signals Cb, and Cr generatedin the color processing circuit to a dynamic random access memory (DRAM)in the memory unit 9 by using the DMA controller. Moreover, theluminance signal Y generated in the color processing circuit is alsosupplied to the AF control unit 12.

The release operation unit 6 is provided with a half-press detector 6-1and a full-pressing detector 6-2. Assuming that the half-press iscompleted, a signal (half-press detection signal) to that effect issupplied to the control unit 10 when a shutter key is depressed by auser, and the half-press detector 6-1 detects that the key reaches apredetermined midpoint point. Then, assuming that the full-pressing iscompleted, a signal (full-press detection signal) to that effect issupplied to the control unit 10 when the full-pressing detector 6detects that the shutter key reaches a lowest point.

The camera operation unit 7 includes various kinds of operation keyssuch as a power-on key and a mode switching key for switching between acapturing mode and a reproduction mode, and the unit 7 supplies adetection signal according to key operation to the control unit 10.

The display device 8 comprises, for example, a liquid crystal display(LCD), and displays a through-image, a captured image, a reproducedimage, and the like based on a video signal supplied from the controlunit 10.

The memory unit 9 comprises a DRAM, a video random access memory (VRAM),a secure digital memory card (SD), and the like.

The control unit 10 comprises, for example, a CPU, a read only memory(ROM), and a random access memory (RAM) (not shown), and controls theoperation of each part of the digital camera 1 according to variouskinds of programs which are stored in the ROM and the like and areappropriately executed by the CPU. Here, the RAM is used as a workmemory when the programs are executed by the CPU.

The control unit 10 reads the luminance signal Y, and the colordifference signals Cb and Cr, which have been obtained from the DMAcontroller through DMA transfer, and writes the read signals into aVRAM. Subsequently, the control unit 10 periodically reads the luminancesignal Y and the color difference signals Cb and Cr from the VRAM, andgenerates a video signal. Then, the video signal is supplied to thedisplay device 8. Thereby, a through-image is displayed on the displaydevice 8.

The lens driving motor unit 11 comprises, for example, a stepping motor,and moves the focus lens in the direction of an optical axis by steppingdrive according to stepping drive instructions and instructions fornormal-reverse rotation of the motor, which are supplied from the AFcontrol unit 12.

The AF control unit 12 performs focusing by stepping drive of the lensdriving motor unit 11, based on the luminance signal supplied from theimage processing unit 5 and by adjusting the position of the focus lensin predetermined steps.

FIG. 2 is a block diagram showing a configuration example of the AFcontrol unit 12. As shown in FIG. 2, the AF control unit 12 comprises afocus evaluation-value calculator 121; a latest evaluation-value memory122; a last evaluation-value memory 123; a peak detector 124; and afocusing-motor controller 125.

The focus evaluation-value calculator 121 comprises a high pass filter,an integrator, and the like (not shown), and extracts the high frequencycomponent of the luminance signal Y which is supplied from the imageprocessing unit 5, by using the high pass filter. Then, the focusevaluation-value calculator 121 integrates the high frequency componentof the luminance signal Y, which has been extracted with the high passfilter, and the integrated value (a value denoting contrast), which hasbeen obtained as described above, is acquired as an AF evaluation value.

The latest evaluation-value memory 122 stores the latest AF evaluationvalue (the latest evaluation value) A, which has been acquired in thefocus evaluation-value calculator 121, and the last evaluation-valuememory 123 stores the AF evaluation value (the last evaluation value) Bwhich has been acquired in the last processing.

The peak detector 124 compares the latest evaluation value A stored inthe latest evaluation-value memory 122, and the last evaluation value Bstored in the last evaluation-value memory 123, and detects the peak ofthe AF evaluation values, that is, a focused position, based on thecomparison result.

More specifically, when it is found from the comparison result that thelatest evaluation value A is larger than the last evaluation value B,operation for detecting the peak is continued, assuming that the AFevaluation value has not reached the peak. When it is found from theresult that the latest evaluation value A is smaller than the lastevaluation value B, an AF termination signal instructing the focus lockis supplied to the focusing-motor controller 125 and the control unit10, assuming that the AF evaluation value has reached the peak.

The focusing-motor controller 125 controls rotating operation of thelens driving motor unit 11, based on the full-press detection signal andthe half-press detection signal, which are supplied from the releaseoperation unit 6.

More specifically, when the half-press detection signal is supplied fromthe release operation unit 6, a pulse signal with a predetermined periodincluding stepping drive instruction and the instruction fornormal-reverse rotation of the motor is supplied to the lens drivingmotor unit 11. Then, the focus lens is moved from the side of near pointto the side of infinite distance at the rate of a predetermined numberof steps per unit period by stepping drive of the lens driving motorunit 11.

When the full-press detection signal is supplied from the releaseoperation unit 6, a pulse signal with a period shorter than that of thecase in which the half-press detection signal is supplied is supplied,whereby the rotational speed of the lens driving motor unit 11 isincreased, and the number of steps by which the focus lens is movedduring the unit period is increased. As described above, the movingspeed of the focus lens at full-pressing of the shutter key can beincreased in comparison with that at the half pressing of the shutterkey.

Furthermore, when the AF termination signal is supplied from the peakdetector 124, the focus lens is returned to the last position by reverserotation of the lens driving motor unit 11 according to the suppliedpulse signal including an instruction for reverse rotation of the motorby which rotation is instructed to be in the opposite direction to thatof the case in which the full-pressing signal, or the half pressingsignal is supplied. Thus, the focus lens is set at the focused position.

Subsequently, concrete operations of the digital camera with theabove-described configuration will be explained.

FIG. 3 is a flowchart showing the concrete operations of the digitalcamera. When the power supply of the digital camera 1 is turned into theON state, the control unit 10 executes necessary processing for initialsetting such as resetting of the RAM, the DRAM, and the VRAM, andsetting for on-board registers at first. In the processing for theinitial setting, the digital camera 1 is set in a through mode, and athrough-image is displayed on the display device 8 (step P1).

When the shutter key is half pressed by a user, and a half-press signalis supplied from the half-press detector 6-1 (YES in step P2), the AFcontrol unit 12 starts automatic-focusing processing, and, thefocusing-motor controller 125 controls the lens driving motor unit 11 tomove the focus lens to an initial position (step P3). Here, the initialposition is configured to be changed according to set capturing modes.Usually, the lens is moved to the nearest point for a normal mode; andto a position at the infinite distance for a macro mode.

Next, the AF control unit 12 calculates an AF evaluation value, based ona luminance signal Y supplied from the image processing unit 5, in thefocus evaluation-value calculator 121 (step P4). Then, after the AFcontrol unit 12 shifts the kept content of the latest evaluation-valuememory 122 to the last evaluation-value memory 123 (step P5), the AFevaluation value calculated by processing in step P4 is stored into thelast evaluation-value memory 123 (step P6).

Subsequently, the AF control unit 12 compares the latest evaluationvalue A stored in the latest evaluation-value memory 122 and the lastevaluation value B stored in the last evaluation-value memory 123, inthe peak detector 124 (step P7).

When the latest evaluation value A is larger than the last evaluationvalue B (YES in step P7), the AF control unit 12 determines that the AFevaluation value has not reached the peak value yet, and subsequently,determines whether or not the shutter key is fully pressed by a user(step P8). Concretely, it is determined whether or not the full-pressdetection signal is supplied from the full-pressing detector 6-2.

As a result, when it is determined that the shutter key is not fullypressed (NO in step P8), it is determined whether or not the half-pressdetection signal from the half-press detector 6-1 is remained in the ONstate, that is, it is determined (step P9) whether or not the shutterkey is kept in the half pressed state.

When the shutter key is kept in the half pressed state (YES in step P9),the AF control unit 12 determines that the automatic-focusing processingis required to be continued, and supplies a pulse signal with a periodof 2 T from the focusing-motor controller 125 to the lens driving motorunit 11 for stepping drive of the lens driving motor unit 11. Thereby,the focus lens is moved from the side of near point to the side ofinfinite distance by a step distance a (step P10). Thereafter,processing in the AF control unit 12 returns to that of step P4.

On the other hand, when the shutter key is not half pressed (NO in stepP9), the AF control unit 12 determines that the automatic-focusingprocessing is required to be completed, and the processing returns tothe processing in step P1, in which the unit 12 waits until the shutterkey is half pressed again.

Moreover, when it is determined that the shutter key is fully pressed inthe processing in step P8 (YES in step P8), the AF control unit 12assumes that a user gives an instruction for capturing, and supplies apulse signal with a period shorter than that of the case in which theshutter key is in the half-press state from the focusing-motorcontroller 125 to the lens driving motor unit 11. Thereby, the lensdriving motor unit 11 performs stepping drive at a higher speed thanthat of the case in which the shutter key is in the half-press state,and the focus lens is moved from the side of near point to the side ofinfinite distance by distance 2 a (step P11). Thereafter, processing inthe AF control unit 12 returns to that of step P4.

When the latest evaluation value A reaches equal to or smaller than thelast evaluation value B (NO in step P7) after processing in steps P4through P11 is repeated, the AF control unit 12 controls the lensdriving motor unit 11 in the focusing-motor controller 125 forrotational driving in the opposite direction to that of the case inwhich the shutter key is fully pressed, or is half pressed, and thefocus lens is returned to the last position. Thus, the focus lens is setat the focused position. At this time, the AF termination signal issupplied from the AF control unit 12 to the control unit 10.

Then, when the AF termination signal is supplied from the AF controlunit 12, it is determined in the control unit 10 (step P12) whether ornot the shutter key has been fully pressed by a user. When the shutterkey has been fully pressed (YES in step P12), capturing processing (stepP13), and storage processing (step P14) are sequentially executed. Whenthe shutter key has not been in the full pressed state (NO in step P12),the control unit 10 waits under looping until the shutter key is fullypressed and YES is obtained in step P12.

Here, the capturing processing in step P13 and the storage processing instep P14 will be explained. The control unit 10 temporally interrupts apath from the DMA controller to the DRAM at the DMA transfer of theluminance signal Y and the color difference signals Cb and Cr for oneframe from the DMA controller to the DRAM. Subsequently, the controlunit 10 generates image data in a predetermined format to store thegenerated data into a SD memory card one by one after the luminancesignal Y, the color difference signals Cb and Cr for one frame are readout from the DRAM every predetermined unit of signals and arecompressed. Then, the control unit 10 reconnects the interrupted pathwhen the storage of the image data for one frame is completed. Thus, thecapturing and storage of images are executed in the digital camera 1.

The above-described description has been made for concrete operationsexecuted in the digital camera 1.

Next, automatic-focusing processing in steps P3 through S11 will be morespecifically explained, assuming as one example that the shutter key isfully pressed before a focused state is obtained. FIG. 4 is a graphshowing a relation between the positions of the focus lens and the AFevaluation values.

As shown in FIG. 4, when the shutter key is half pressed by a user atT=T0 (YES in step P3), the AF control unit 12 moves the focus lens tothe initial position (step P4). Subsequently, the focus lens is drivenfrom the side of near point to the side of infinite distance in the lowspeed at a speed of a per unit time (step P10).

Thereafter, the processing in step P10 is executed till T=T4 duringwhich the shutter key is fully pressed, during which the focus lensadvances to a point of 4 a (search point). Then, when the shutter key isfully pressed by a user at T=T4 (YES in step P8), the AF evaluationvalue has not reached the peak at this point yet (YES in step P7).Accordingly, the AF control unit 12 accelerates the driving speed of thefocus lens to a speed of 2 a per unit time for starting of high-speeddriving (step P11).

Thereafter, processing in steps P4 through P11 is repeated till T=T7,during which the focus lens advances to a point of 10 a (search point).Then, when it is determined at T=T7 (NO in step P7) that the AFevaluation value is lowered, the AF control unit 12 determined that theAF evaluation value has reached the peak at T=T6, and the focus lens isreturned to a point of 8 a a at a speed of 2 a per unit time. Thereby,the focus lens is set at the focused position.

As explained above, the digital camera 1 according to the firstembodiment has a configuration in which the focus lens is moved at ahigher speed than that of the case in which the shutter key is halfpressed and the focused position is detected when the shutter key isfully pressed by a user before the focus lens reaches the focusedposition. Thereby, the digital camera 1 can achieve focusing with lessdelay in capturing even when the shutter key is fully pressed by a userbefore the focus lens reaches the focused position.

The first embodiment has a configuration in which AF processing inlow-speed mode and AF processing in high-speed mode are prepared in theAF method of a contrast detection type, the AF processing in low-speedmode and the AF processing in high-speed mode are switched according totiming of half pressing and that of full-pressing of the shutter key asshown in the flowchart of FIG. 3, a moving amount of the focus lens forone frame (step interval) is decreased during the AF processing inlow-speed mode, and a moving amount of the focus lens for one frame(step interval) is increased during the AF processing in high-speedmode. However, a method for shortening focusing time during the AFprocessing in high-speed mode and the AF processing in low-speed mode isnot limited to this embodiment, and there is a method for shorteningfocusing time as described in, for example, the after-described sixmodified examples.

The above-described embodiment has a configuration in which the focuslens is stopped at search (capturing) points (boundary points betweensteps), and the moving speed of the focus lens during the AF processingin low speed mode is the same as that of the AF processing in high speedmode. However, when the focus lens is not stopped at the search points,a similar AF evaluation value to that of the above embodiment can beacquired at the same search points as those of the embodiments by aconfiguration in which the moving speed of the focus lens is reducedduring AF processing in low-speed mode, and the moving speed of thefocus lens is made higher than that of the AF processing in low-speedmode.

FIG. 5 is a flowchart showing the outline of the AF operations by whichthe AF processing in low-speed mode and the AF processing in high-speedmode are switched according to timing of half pressing and that offull-pressing of the shutter key, and shows basic points common to thefirst embodiment and the modified examples 1 to 6 (will be describedlater).

In FIG. 5, when the power supply of the digital camera 1 is turned intothe ON state, the control unit 10 executes necessary initial settingsuch as resetting of the RAM, the DRAM, and the VRAM, and setting foron-board registers (step Q0).

Subsequently, automatic exposure (AE) processing for the through-imageis executed by using a focal length corresponding to a zoom value at thetime, and the through-image is displayed on the display device 8 (stepQ1).

The control unit 10 determines whether or not the shutter key is halfpressed, that is, whether or not the half-press detection signal issupplied from the half-press detector 6-1. When the shutter key is halfpressed, the processing proceeds to step Q3; and when not half pressed,the control unit 10 waits until the shutter key is half pressed (stepQ2).

When the shutter key is half pressed, the control unit 10 furtherdetermines whether or not the shutter key is fully pressed, that is,whether or not the full-press detection signal is supplied from thefull-pressing detector 6-2 (step Q3). When fully pressed, the processingproceeds to step Q5, and, when not fully pressed (that is, in a case inwhich the shutter key is remained in the half pressing state), theprocessing proceeds to step Q4.

When the shutter key is not fully pressed, the AF processing inlow-speed mode (refer to explanations of the first embodiment (steps P3through P7, and P10 in FIG. 3), and the modified examples 1 to 6) isexecuted, and thereafter, the AF processing in low-speed mode iscontinued (step Q4) until it is detected in step Q3 that the shutter keyis fully pressed. When the AF processing in low-speed mode is completedbefore it is detected that the shutter key is fully pressed, noprocessing is performed in step Q4, and the control unit 10 waits instep Q3 until the shutter key is fully pressed.

When it is detected in step Q3 that the shutter key is fully pressed,the control unit 10 determines whether or not the AF processing (thatis, the AF processing in low-speed mode in step Q4, or the AF processingin high-speed mode in step Q6) is completed, that is, whether or not theAF termination signal is supplied from the AF control unit 12 (step Q5).When the AF processing is completed, the processing proceeds to step Q7,and when not completed, the processing proceeds to step Q6. Even whenthe AF processing in low-speed mode at step Q4 is not completely endedand when processing in which the AF search processing in low-speed modeis completed and the focus lens is under moving to a focused position,it is determined in step Q5, that the AF processing is completed, andthe processing proceeds not to AF processing in high-speed mode in stepQ6, but to capturing processing and the record processing in step Q7after moving of the focus lens to the focused position is completed.

When it is determined that the AF processing is not completed in stepQ5, the AF processing in high-speed mode (refer to explanations of thefirst embodiment (steps P3 through P7, and P11 in FIG. 3), and themodified examples 1 to 6) is executed. Thereafter, the AF processing inhigh-speed mode is continued until it is detected in step Q5 that the AFprocessing is completed. Moreover, when the AF processing in low-speedmode is not completed at a point when the shutter key is fully pressed,the processing is switched from the AF processing in low-speed mode instep Q4 to the AF processing in high-speed mode, and the focusedposition is configured to be detected through the AF processing inlow-speed mode and the AF processing in high-speed mode (step Q6).

Immediately after it is determined that the AF processing is completedin step Q5, the processing is switched to a CCD drive method for theimage capturing to execute image compression processing of the capturedimage data, and compressed image data (image file) is recorded tocomplete capturing of images for one frame (step Q7).

Furthermore, the AF processing in low-speed mode in step Q4 and the AFprocessing in high-speed mode in step Q6 will be explained in theafter-described modified examples 1 to 6 according to the firstembodiment. Moreover, when AF processing is executed in such a way thatthe moving amount (step interval) of the focus lens for one frame isdecreased in step Q4, and the moving amount (step interval) of the focuslens for one frame is increased in step Q6 by controlling the lensdriving motor unit 11 through the AF control unit 12, the AF operationsare similar to those for the first embodiment.

Moreover, the flowchart shown in FIG. 5 can be applied to a case inwhich full-pressing (AF operation in high-speed mode) can be startedwithout half pressing (AF processing in low-speed mode) of the shutterkey. For example, there may be adopted a configuration in which, whenthe shutter key is pressed at one stroke in steps Q2 and Q3 in FIG. 5,half-press operation is not started unless the shutter key is kept halfpressed for equal to, or longer than a predetermined time as will bedescribed in an example shown in FIG. 19 later. When the aboveconfiguration is adopted, it is determined that the shutter key ispressed at one stroke if the shutter is fully pressed within thepredetermined time after the shutter key is half pressed, and the AFprocessing in high-speed mode in step Q6 is executed without executingAF processing in low-speed mode in step Q4.

Moreover, as a method for determining that the shutter key is pressed atone stroke, another method may be adopted. In the method, by installinga shutter key by which the half-press operation can not be electricallydetected (recognized) unless the half-press operation is kept for apredetermined time, it is repeatedly determined whether the shutter keyis fully pressed or the shutter key is half pressed. Then, the AFprocessing in high-speed mode in step Q6 is executed without executingAF processing in low-speed mode in step Q4, based on determination thatthe shutter key is pressed at one stroke, when it is determined withoutdetermination in which the shutter key is half pressed that the shutterkey is fully pressed.

FIRST MODIFIED EXAMPLE

There may be adopted a configuration as follows in which, based onswitching the AF processing in low-speed mode and the AF processing inhigh-speed mode according to timing of half pressing and that offull-pressing of the shutter key, a moving speed of the focus lensduring the AF processing in high-speed mode is increased more than thatduring the AF processing in low-speed mode. AF processing time can beshortened by an amount by which the moving speed of the focus lensincreased.

Concretely, step Q4 in the flowchart shown in FIG. 5 may have aconfiguration in which “the control unit 10 controls the AF control unit12 to start the AF processing of the contrast detection type includingprocessing by which the focus lens is moved at a predetermined movingspeed V1”. In addition, step Q6 in the flowchart shown in FIG. 5 mayhave a configuration in which “the control unit 10 controls the AFcontrol unit 12 to start the AF processing of the contrast detectiontype including processing by which the focus lens is moved at a movingspeed V2 higher than the speed V1”.

According to the first modified example, the interval between searchpoints at the AF processing in high-speed mode is longer than theinterval between search points at the AF processing in low-speed mode inthe same manner as that of the first embodiment, for example, when theframe rate of the CCD at AF processing in low-speed mode, and that at AFprocessing in high-speed mode are the same with each other. Moreover,the interval between search points at the AF processing in high-speedmode and that at the AF processing in low-speed mode can be configuredto be the same by a configuration in which the frame rate of the CCD atAF processing in low-speed mode is faster than that at AF processing inhigh-speed like the after-described second modified example.

Here, the first modified example is effective for either a case in whichthe focus lens is temporarily stopped at search points, or a case inwhich the focus lens is not stopped at search points.

SECOND MODIFIED EXAMPLE

There may be adopted a configuration as follows in which, based onswitching the AF processing in low-speed mode and the AF processing inhigh-speed mode according to timing of half pressing and that offull-pressing of the shutter key, a user can easily follow a movingsubject by displaying a through-image even at AF processing in low-speedmode, and AF processing is executed at a higher frame rate byinterrupting display of a through-image at AF processing. For example,during AF processing in high-speed mode, the frame rate can be increasedby extracting a part of a CCD (image capture element 3) for driving, orby reading out combined pixels for driving. Even in a state in which theframe rate is increased and the moving speed of the focus lens is moreincreased by an amount corresponding to the increased amount of theframe rate, the accuracy of AF processing can be maintained because anumber of search points are not required to be decreased. The focusingtime can be shortened because, based on a configuration in which onlyone third of pixels among all pixels in the CCD are read out, the framerate is increased by an amount (three times in this example)corresponding to the decreased amount of the pixels, and the movingspeed of the focus lens can be increased.

Concretely, step Q4 in the flowchart shown in FIG. 5 may have aconfiguration in which “the control unit 10 controls the AF control unit12 to start the AF processing of the contrast detection type includingprocessing by which the focus lens is moved at a first moving speed,and, at the same time, to display a through-image on the display device8 during the above processing until the shutter key is fully pressed”.In addition, step Q6 in the flowchart shown in FIG. 5 may have aconfiguration in which “the control unit 10 interrupts display of athrough-image, and reads out a part of the CCD for driving to increase aframe rate to a value higher than that of AF processing in low-speedmode, and, at the same time, the control unit 10 controls the AF controlunit 12 to start the AF processing of the contrast detection typeincluding processing by which the focus lens is moved at a second movingspeed higher than the first speed”. Here, this modified example 2 iseffective for either a case in which the focus lens is temporarilystopped at search points, or a case in which the focus lens is notstopped at search points.

THIRD MODIFIED EXAMPLE

Moreover, there may be adopted a configuration as follows. Based onswitching the AF processing in low-speed mode and the AF processing inhigh-speed mode according to timing of half pressing and that offull-pressing of the shutter key, an approximate focus position (focusedposition) 72 is detected by rough AF search processing with a largemoving amount 71 of the focus lens for one frame (=long step interval(interval between lens positions)) during the AF processing in low-speedmode as shown in FIG. 8A. Subsequently, an exact focus position 77 isdetected by detailed AF search processing with a small moving amount 76of the focus lens (=short step interval) in the vicinity of the detectedfocus position at AF processing in low-speed mode. During the AFprocessing in high-speed mode, only rough AF search processing with alarge moving amount 71 of the focus lens for one frame is performed,that is, AF search processing with a small moving amount 76 of the focuslens is omitted during AF processing in high-speed mode.

For example, when the shutter key is fully pressed during AF processingin low-speed mode, and rough AF search processing is underway at thefull-press time, the focus position is obtained only by the rough AFsearch processing without the detailed AF search processing aftercompleting the rough AF search processing.

Moreover, there may be adopted a configuration in which, when AFprocessing in low-speed mode is switched to AF processing in high-speedmode, and detailed AF search processing is underway at the switching,switching to intermediate rough search processing is performed under amoving amount (=within a step interval) 78 of the focus lens for oneframe as shown in FIG. 8B. Further, when the shutter key is fullypressed during the AF processing in low-speed mode, and the detailed AFsearch processing is underway at the full-press time, the detailed AFsearch processing may be continued.

The approximate focus position is obtained by rough AF search processingat first. Then, the exact focus position is obtained with a narrowsearch interval including the approximate focus position according totwo-step AF processing during the AF processing in low-speed mode. Afocus position is obtained only by rough AF search processing during theAF processing in high-speed mode as described above. Consequently,necessary time can be shortened by an amount by which detailed AF searchprocessing is not performed, and finally, focusing time can be reducedby an amount by which the moving speed of the focus lens increased.

Concretely, as shown in the flowchart of FIG. 9, step Q4 in theflowchart shown in FIG. 5 may have a configuration in which, “when theshutter key is not fully pressed, the control unit 10 determines whetheror not an approximate focused position 72 has been detected, and theprocessing proceeds to step Q4-4 when the approximate focused position72 has been detected, or the processing proceeds to step Q4-2 when isnot detected (step Q4-1)”.

In addition, the above step Q4 may have a configuration in which “thecontrol unit 10 first instructs the AF control unit 12 to drive the lensdriving motor unit 11 for AF search processing with a rough searchinterval 71 as shown in FIG. 8A under a large moving amount of the focuslens for one frame, when an approximate focused position 72 has not beendetected (step Q4-2); and, when a focus evaluation value for the currentlens position is determined and an approximate focused position 72 isdetected, the processing proceeds to step Q4-4, and, when not detected,the processing returns to step Q3 (step Q4-3)”.

Moreover, the above step Q4 may have a configuration in which “thecontrol unit 10 instructs the AF control unit 12 to drive the lensdriving motor unit 11 for AF search processing with a detailed searchinterval 76 when the approximate focused position is detected in stepQ4-3 (step Q4-4)”.

Furthermore, no processing is not performed in step Q4-4 after the focusevaluation value of the current lens position is determined in step Q4-4to detect the focused position 77, and the focus lens is moved to thefocused position 77.

Thereby, the approximate focus position (focused position) 72 can bedetected by rough AF search processing with a large moving amount of thefocus lens for one frame, and, subsequently, the exact focus position 77can be detected by detailed AF search processing with a small movingamount of the focus lens in the vicinity of the detected focus position.

Moreover, as shown in the flowchart of FIG. 10, step Q6 in the flowchartshown in FIG. 5 may have a configuration in which “when AF processing inlow-speed mode has not been completed, the control unit 10 determineswhether or not the detailed AF search processing in step Q4-4 in FIG. 9is underway (step Q6-1), and the processing proceeds to step Q6-2 whenthe detailed AF search processing is underway, or the processingproceeds to step Q6-3 when the rough AF search processing is underway”;“when detailed AF search processing is underway, the control unit 10immediately stops detailed AF search processing, that is, AF processing,and the processing proceeds to step Q5 after the focus lens position atthe stopping time is set as the focused lens position (step Q6-2)”; and“when the rough AF search processing is underway, the control unit 10continuously instructs the AF control unit 12 to drive the lens drivingmotor unit 11 for AF search processing under a large moving amount ofthe focus lens for one frame as shown in FIG. 8A, and the processingreturns to step Q5 (step Q6-3)”.

Thereby, when AF processing in low-speed mode is switched to AFprocessing in high-speed mode, and detailed AF search processing isunderway at the switching, the detailed AF search processing is stopped.When rough AF search processing is underway at the switching of the AFprocessing, the rough AF search processing is continuously performed.

FOURTH MODIFIED EXAMPLE

Moreover, there may be adopted a configuration in which, based onswitching the AF processing in low-speed mode and the AF processing inhigh-speed mode according to timing of half pressing and that offull-pressing of the shutter key, exposure time for one frame isincreased at AF processing in low-speed mode, and, at AF processing inhigh-speed mode, exposure time for one frame is shorter than theexposure time at the AF processing in low-speed mode. Thereby, in thecase in which the focus lens is stopped at AF search points, AFprocessing time can be shortened by an amount by which stopping time ismade shorter by the shorter exposure time, and even in the case in whichthe focus lens is not stopped at AF search points, the AF processingtime can be reduced by an amount by which a frame rate is made higher bythe shorter exposure time.

Concretely, step Q4 in the flowchart shown in FIG. 5 may have aconfiguration in which, “the control unit 10 controls the AF controlunit 12 to start the AF processing of the contrast detection type bymaking the exposure time for one frame longer. In addition, step Q6 inthe flowchart shown in FIG. 5 may have a configuration in which, “thecontrol unit 10 controls the AF control unit 12 to start the AFprocessing of the contrast detection type by making the exposure timefor one frame shorter than the exposure time at AF processing inlow-speed mode.”

FIFTH MODIFIED EXAMPLE

Moreover, there may be adopted a configuration in which, based onswitching the AF processing in low-speed mode and the AF processing inhigh-speed mode according to timing of half pressing and that offull-pressing of the shutter key, a moving range (AF search range) FW1of the focus lens is made wider at AF processing in low-speed mode, anda moving range FW2 of the focus lens is made narrower at AF processingin high-speed mode, as shown in FIG. 11. Here, when, assuming that themoving range FW2 is completely included within the moving range FW1 asshown in FIG. 11, switching is made to AF processing in high-speed modeduring AF processing in low-speed mode, and AF search processing with anarrow moving range FW2 has already been completed at the switching, AFsearch processing (AF processing) is required to immediately becompleted. Moreover, under a state in which switching is made to AFprocessing in high-speed mode during AF processing in low-speed mode,and AF search processing with a narrow moving range FW2 has not beencompleted at the switching, AF search processing is continued till theAF search processing with a narrow moving range FW2 is completed whenthe AF search processing with a narrow moving range FW2 is underway.When the AF search processing with a narrow moving range FW2 is notunderway, AF search processing with a narrow moving range FW2 isperformed after the focus lens is moved to the end of the narrow movingrange FW2 without AF search processing.

Thereby, focusing time is shortened because the number of times thefocus lens is stopped (driving time of the focus lens), that of timescontrast data is acquired, that of times the contrast data is compared,and the like are small under a state in which the moving range of thefocus lens at AF processing in high-speed mode is narrower in comparisonof the range between AF processing in low-speed mode. Furthermore,focusing time is shortened as a whole by combination of AF processing inlow-speed mode and AF processing in high-speed mode even when theshutter key is fully pressed during AF processing in low-speed mode.

Concretely, step Q4 in the flowchart shown in FIG. 5 may have aconfiguration in which, “the control unit 10 controls the AF controlunit 12 to perform the AF processing of the contrast detection type byAF search processing with a wide moving range FW1.” In addition, step Q6in the flowchart shown in FIG. 5 may have a configuration in which, “thecontrol unit 10 controls the AF control unit 12 to perform the AFprocessing of the contrast detection type by AF search processing with anarrow moving range W2.”

SIXTH MODIFIED EXAMPLE

Moreover, the above described first embodiment and the first to fifthmodified examples, which have been described above, may be combined forthis invention. FIG. 6 is a table summarizing operations of AFprocessing in low-speed mode and AF processing in high-speed modeaccording to the first embodiment and the first to fifth modifiedexamples. FIG. 7 is a view showing combination examples of AF processingbased on AF processing in low-speed mode and AF processing in high-speedmode, and shows combinations by which AF processing can be realized byselecting two of combinations of the first embodiment and the first tofifth modified examples, depending on AF processing in low-speed modeand AF processing in high-speed mode. In the combination fields in FIG.7, a symbol “Z” denotes the first embodiment, and symbols “H1” to “H5”denote the first to fifth modified examples, respectively.

For example, in, FIG. 7, a combination of “H5, Z” which is one ofexamples combining two of the first embodiment and the first to fifthmodified examples means, as described in FIG. 6, that, during AFprocessing in low-speed mode, the focus lens is moved within a widemoving range of the focus lens (fifth modified example) under a smallmoving amount (step interval) of the focus lens for one frame (firstembodiment); and, during AF processing in high-speed mode, the focuslens is moved within a narrow moving range of the focus lens (fifthmodified example) under a large moving amount (step interval) of thefocus lens for one frame (first embodiment).

Furthermore, a combination of “H2, H1” means that, during AF processingin low-speed mode, the focus lens is moved with a small moving amount ofthe focus lens for one frame (first modified example) in order todisplay a through-image (second modified example); and, during AFprocessing in high-speed mode, the focus lens is moved with a largemoving amount of the focus lens for one frame under a state in whichdisplay of a through-image is stopped.

Moreover, the examples in FIG. 7 have shown the examples combining twoof the first embodiment and the first to fifth modified examples, butexamples combining 3 to 5 of the first embodiment and the first to fifthmodified examples may be applied to this invention. For example, acombination of “H4, H5, H3” means that, during AF processing inlow-speed mode, AF exposure time for one frame is increased (fourthmodified example); AF search processing is roughly performed within awide range of the focus lens (fifth modified example) under a largemoving amount of the focus lens for one frame to detect an approximatefocus position; and, thereafter, detailed AF search processing isperformed with a small moving amount of the focus lens in the vicinityof the detected focus position to detect an accurate focus position(third modified example); during AF processing in high-speed mode, AFexposure time for one frame is shortened (fourth modified example), andAF search processing is roughly performed (third modified example)within a narrow range of the focus lens (fifth modified example) under alarge moving amount of the focus lens for one frame.

Other embodiments of the present invention according to the presentinvention will be described. The same portions as those of the firstembodiment will be indicated in the same reference numerals and theirdetailed description will be omitted.

Second Embodiment

The first embodiment has a configuration in which AF processing inlow-speed mode and AF processing in high-speed mode are provided in anAF method of a contrast detection type; the AF processing in low-speedmode is executed from a point at which a shutter key is half pressed toa point at which the shutter key is fully pressed; and the AF processingin low-speed mode is switched to the AF processing in high-speed modewhen the shutter key is fully pressed. However, there may be applied aconfiguration in which AF necessary time is predicted at a point atwhich the shutter key is fully pressed for a case in which AF processingin low-speed mode is continuously executed, and for a case in which AFprocessing in high-speed mode is executed from the beginning, and AFprocessing is executed according to mode in which the predictednecessary-time is shorter.

FIG. 12 is a flowchart showing the content for concrete operations of adigital camera according to the second embodiment. FIGS. 13A and 13B areviews each showing a relation between the positions and AF evaluationvalues when switching is made to AF processing in high-speed mode duringAF processing in low-speed mode.

In FIG. 12, when the power supply of a digital camera 1 is turned intothe ON state, the control unit 10 executes necessary initial settingsuch as resetting of the RAM, DRAM, and VRAM, and setting for on-boardregisters at first (step R0).

Subsequently, AE processing for a through-image is executed, using afocal length corresponding to a zoom value at the time, and thethrough-image is displayed on the display device 8 (step R1).

The control unit 10 determines whether or not the shutter key is halfpressed, that is, whether or not a half-press detection signal issupplied from the half-press detector 6-1. When the shutter key is halfpressed, the processing proceeds to step R3, and when not half pressed,the control unit 10 waits until the shutter key is half pressed (stepR2).

When the shutter key is half pressed, the control unit 10 furtherdetermines whether or not the shutter key is fully pressed, that is,whether or not a full-press detection signal is supplied from thefull-pressing detector 6-2. When fully pressed, the processing proceedsto step R5, and when not fully pressed (that is, in a case in which theshutter key is remained in the half pressing state), the processingproceeds to step R4 (step R3).

When the shutter key is not fully pressed, the processing returns tostep R3 after AF processing in low-speed mode (first embodiment (referto the explanation for FIG. 3)) is executed for one frame (step R4).

When the shutter key is fully pressed, the control unit 10 determineswhether or not the AF processing (that is, the AF processing inlow-speed mode in step R4) is completed, that is, whether or not the AFtermination signal is supplied from the AF control unit 12. When the AFprocessing is completed, the processing proceeds to step R13, and, whennot completed, the processing proceeds to step R6 (step R5).

When AF processing (AF processing in low-speed mode in step R4) is notcompleted at full-pressing of the shutter key (for example, a case shownin FIG. 13A), the control unit 10 calculates necessary time A forfocusing from the current time under a state in which AF processing inlow-speed mode is continuously executed, and necessary time B forfocusing from the current time under a state in which AF processing inhigh-speed mode is executed from the beginning (step R6). Furthermore,when the necessary time A for focusing and the necessary time B forfocusing are compared, the processing proceeds to step R8 in the case ofA>B, and the processing proceeds to step R11 in the case in which A isnot larger than B (step R7).

When the necessary time A for focusing is longer than the necessary timeB for focusing, the control unit 10 resets the position of the focuslens (step R8), and AF processing in high-speed mode (first embodiment(refer to the explanation for FIG. 3)) is executed for one frame (stepR9) in order to execute AF processing in high-speed mode from thebeginning as shown in FIG. 13B. Furthermore, it is determined (step R10)whether or not AF processing (that is, AF processing in high-speed modein step R9) is completed, that is, whether or not the AF terminationsignal is supplied from the AF control unit 12. The processing proceedsto step R13 when the AF processing is completed, and the processingreturns to step R9 when not completed.

When the necessary time A for focusing is equal to or shorter than thenecessary time B for focusing, the control unit 10 continuously executesAF processing in low-speed mode (first embodiment (refer to theexplanation for FIG. 3)) for one frame from the position of the focuslens at full-press of the shutter key of step R3 (step R11).Furthermore, it is determined whether or not AF processing (that is, AFprocessing in low-speed mode) is completed, that is, whether or not theAF termination signal is supplied from the AF control unit 12. Theprocessing proceeds to step R13 when the AF processing is completed, andthe processing returns to step R11 when not completed (step R12).

When the AF processing is completed in step R10 or R12, the processingis switched to a CCD drive method for the image capturing to executeimage compression processing of the captured image data, and compressedimage data (image file) is recorded to complete capturing of images forone frame (step R13).

According to operations in the flowchart shown in FIG. 12, AF operationafter full-pressing of the shutter key depends on AF processing withshorter necessary time for focusing, either of AF processing inlow-speed mode or AF processing in high-speed mode according to timingof full-pressing of the shutter key. Therefore, the digital camera 1 canachieve focusing with less delay in capturing even when the shutter keyis fully pressed by a user before the focus lens reaches the focusedposition.

There may be applied a configuration in which, when, in the flowchart ofFIG. 12, steps R6, R7, R11, and R12 are omitted, and it is determined instep R5 that AF processing in low-speed mode is not completed, theprocessing proceeds to step R8, and AF processing in high-speed mode isexecuted from the beginning.

Configurations of the AF control unit 12 according to the firstembodiment, the first to sixth modified examples, and the secondembodiment can be obviously realized with hardware, and, at the sametime, and the above configurations may be realized by use of softwareprocessing in the control unit 10. In this case, there may be applied aconfiguration in which the control unit 10 functions as AF control unit12, programs realizing the above-described various kinds of processingare stored in the digital camera 1 (for example, ROM), and the controlunit 10 executes the above programs.

Then, the digital camera 1 in which the above programs have beeninstalled beforehand can be obviously provided, and an existing digitalcamera to which the above programs are applied can also function as thedigital camera 1 according to the embodiments.

Moreover, a method by which the programs in the first and secondembodiments are provided is arbitrary. The programs can be provided, forexample, a communication medium such as the Internet; and the programsmay be distributed in a form that the programs are stored in recordingmedium such as a memory card.

Third Embodiment

FIGS. 14A to 14C are views showing the appearance of a digital camera asone example of an image capture device according to third and fourthembodiments of this invention (hereinafter, called digital camera): FIG.14A is a front view; FIG. 14B is a rear view; and FIG. 14C is a topview.

In FIGS. 14A to 14C, a digital camera 50 comprises an image capture lens52 and with a stroboscopic light-emitting window 51 on the front asshown in FIG. 14A. Further, a mode dial 53, a liquid-crystal displayscreen 54, a cursor key 55, a set key 56, and the like are provided onthe back of the digital camera 50 as shown in FIG. 14B. In addition, azoom lever 57, a shutter key 58, a power supply button 59, a key forsetting a stroboscopic light-emitting mode 60 are provided on the uppersurface as shown in FIG. 14C. A universal serial bus (USB) terminalconnection section used for a case in which external devices such as apersonal computer (hereinafter, called a PC) and a modem are connectedto a USB cable are provided on the side surface, though the USB terminalconnection section is not shown in the drawing.

FIG. 15 is a diagram showing one example of a configuration for theelectronic circuit of the digital camera shown in FIGS. 14A to 14C. InFIG. 15, the digital camera 50 comprises a zoom driving unit 61-1 bywhich a zoom lens is moved for optical zooming operations in a capturingmode which is a basic mode; a AF driving unit 61-2 by which a focusposition is moved by moving a focus lens; an optical lens system 62forming the image capture lens 52 including the zoom lens and the focuslens; a CCD 63 which is an image capture element; a timing generator(TG) 64; a vertical driver 65; a sample-hold circuit (S/H) 66; an A/Dconverter 67; a color processing circuit 68; a direct memory access(DMA) controller 69; a DRAM interface (I/F) 70; a DRAM 71; a controlunit 72; a VRAM controller 73; a VRAM 74; a digital video encoder 75; adisplay device 76; a joint photographic expert group (JPEG) circuit 77;a storage memory 78; a key input device 80 (including the keys 53 to 60of FIGS. 14A to 14C); a flash driving unit 81, and the like. Here, thezoom driving unit 61-1 through the color processing circuit 68 areequivalent to an image pick-up portion in this invention. Moreover, thezoom driving unit 61-1 and the zoom lens are equivalent to opticalzooming portion in this invention.

In the monitoring state under the capturing mode, the zoom driving unit61-1 drives a zoom-lens driving motor unit (not shown) to move the zoomlens. The AF driving unit 61-2 drives a focus-lens driving motor unit(not shown) to move the focus lens to a focused point. Moreover, the CCD63, which is arranged in a rearward position of a capturing optical axisof the optical lens system 62 forming the capturing lens 2 and is animage capture element, is driven for scanning by the timing generator(TG) 64 and the vertical driver 65. In a monitoring state during thecapturing mode, photoelectric conversion output corresponding to anoptical image focused with a constant period is output for one screen.This CCD 63 is a solid state imaging device which forms atwo-dimensional image of a subject, and typically forms tens of framesof images of per second. Here, the image capture element is not limitedto a CCD and may be a solid state imaging device such as a complementarymetal oxide semiconductor (CMOS).

The photoelectric conversion output is adequately subjected to gainadjustment for each primary-color component of RGB in a state of signalsof an analog value, is sampled and held in the sample-hold circuit (S/H)66, is converted into digital data in the A/D converter 67, and issubjected to image-interpolation processing and correction processing inthe color processing circuit 68 to generate a luminance signal Y, andcolor difference signals Cb and Cr with a digital value. Then, theluminance signal Y, and the color difference signals Cb and Cr areoutput to the DMA controller 69.

The DMA controller 69 performs DMA transfer of the luminance signal Y,and the color difference signal Cb, and Cr, which are output from thecolor processing circuit 68, by using a composite synchronous signal, amemory write enable signal, and a clock signal, which are similarlysupplied from the color processing circuit 68, to a DRAM 71 used as abuffer memory through a DRAM interface (I/F) 70.

The control unit 72 has a function of control operation of the wholedigital camera 50, and includes a CPU or a microprocessor unit (MPU)(hereinafter, called a CPU); a program storage memory such as a flashmemory which fixedly stores programs (including an image-formingprogram) for operations, which include control of image-formingoperation and are executed in the CPU as described later; a RAM used asa work memory; and the like. After DMA transfer of the luminance signaland the color difference signal to the DRAM 71 is completed, the controlunit 72 reads out the luminance signal and the color difference signalfrom the DRAM 71 through the DRAM interface 70 for writing into the VRAM74 through the VRAM controller 73.

According to a state signal from the key input device 80, the controlunit 72 takes out an image-forming program and menu data correspondingto each mode, which are stored in the memory for storing programs, suchas a flash memory, and executes control for executing of each functionof the digital camera 50, and executes control for, for example, zoomingoperation, through display, flash driving control, automatic focusing,capturing, recording, reproduction and display of recorded images,display of a function selection menu when a function is selected, anddisplay of a set screen, other than control for capturing operationswhen the shutter key is pressed at one stroke.

The digital video encoder 75 periodically reads out the luminance signaland the color difference signal from the VRAM 74 through the VRAMcontroller 73, and generates a video signal based on the above data, foroutput to the display device 76.

The display device 76 functions as a monitor display device (electronicviewfinder) at capturing mode as described above, and displays imagesbased on the image information, which is captured from the VRAMcontroller 73 at that time, on the liquid-crystal display screen 54 inreal time by display according to video signals from the digital videoencoder 75.

When there is given a focusing instruction (half-press of the shutterkey 58 in this embodiment), the control unit 72 sends a driving controlsignal to the AF driving unit 61-2, and moves the focus lens in theoptical lens system 62 for focusing (AF) operation. When there is givenan image forming instruction (full-pressing of the shutter key 58 inthis embodiment), capturing is executed (that is, a path from the CCD 63to the DMA 71 is immediately interrupted at this point, and switching ismade to a CCD drive method for the image capturing different from themethod used for acquiring a through-image), and the processing ischanged to a recording and reserving state.

In the recording and reserving state, the control unit 72 reads out theluminance signal and the color difference signal for one frame, whichare stored in the DRAM 71, through the DRAM interface 70 for eachcomponent of Y, Cb, and Cr in units, which are named basic blocks, ofeight pixels in the vertical direction×eight pixels in the horizontaldirection, and supplies the above signals to a joint photograph codingexperts group (JPEG) circuit 77 for data compression in the JPEG circuit77 by processing such as adaptive discrete cosine transforming (ADCT)and Huffman coding, that is, entropy coding.

Then, the obtained coded data is read out from the JPEG circuit 77, andis recorded in the storage memory 78, which is a recording medium in thedigital camera 50, as a data file of one image. The control unit 72reconnects the path from the CCD 63 to the DRAM 71 along withcompression processing of the luminance signal and the color differencesignal for one frame, and with completion in writing of the compresseddata into the storage memory 78.

Moreover, at reproduction mode which is a basic mode, the control unit72 selectively reads out image data recorded in the storage memory 78,and the compressed image data is expanded in the JPEG circuit 77according to an inverse procedure to that of data compression at imagecapturing mode. Then, the expanded image data is stored in the VRAM 74after developing through the VRAM controller 73, the image data isregularly read out from this VRAM 74, and, based on these pieces ofimage data, a video signal is generated to output (=display) areproduction image on the liquid-crystal display screen 54 in theoperation unit 76.

The key input device 80 has the above-described mode dial 53, the cursorkey 55, the set key 56, the zoom lever 57, the shutter key 58, the powersupply button 59, the key for setting a stroboscopic light-emitting mode60 and the like, and signals according to operations of the above keysare directly sent out to the control unit 72.

The mode dial 53 switches the recording mode (capturing mode) and thereproduction mode. The cursor key 55 is operated for pointing with acursor on menus, icons, and the like, which are displayed on theliquid-crystal display screen 54 at mode setting, menu selection and thelike.

Moreover, the set key 56 is pressed when an item under cursor displaywith the cursor key 55 is selected for setting or confirming.

The zoom lever 57 is used for zooming operation, and a zoom value isdetermined according to operations of the zoom lever 57 in the case ofdigital zooming, but an actual angle of view is not changed, and animage with a size corresponding to the zoom value after trimming isdisplayed on the liquid-crystal display screen 54. Furthermore, in thecase of optical zooming, the zoom lens (variable-focal-length lens) ismoved to the wide-angle side or the telephoto side according tooperations of the zoom lever 57, a zoom value is determined according tooperations of the zoom lever 57, the angle of view is actually changedin accordance with the change of zoom values, and a wide-angle image ora telephoto image is displayed on the liquid-crystal display screen.Here, this embodiment will be explained, assuming that a digital zoomingfunction is not included, and only an optical zooming function isincluded. But, the present invention can be applied to a digital cameraprovided with the digital zoom function.

The shutter key 58 operates release processing at capturing, and has atwo-stage stroke function. At a first stage (half-press state), afocusing instruction signal is generated in order to execute automaticfocusing (AF), automatic exposure (AE), and automatic white balance(AWB); and at a second stage (full-pressing state), a capturinginstruction signal is generated in order to execute capturing operation.Here, in this embodiment, when the shutter key 58 is fully pressed atone stroke (hereinafter, pressed at one stroke), focusing operationwhich is started by the first stage operation is switched to a simplefocusing operation. When this simple focusing operation is completed,capturing processing is executed to store image data, which has beenobtained by this capturing processing, in the RAM.

Here, there may be adopted a configuration in which two-stage operationcan be performed by installing a touch sensor function in the shutterkey 58, that is, the shutter key is operated for a case in which a usertouches the shutter key 58, and for a case in which the shutter key ispressed. In this case, when the shutter key 58 is touched, the controlunit 72 executes half-press processing, assuming that half-pressoperation is given. When the shutter key 58 is pressed, the control unit72 performs full-press operation, assuming that full-pressing operationis given.

The key for setting a stroboscopic light-emitting mode 60 has astructure of switching by pushing down, that is, a configuration inwhich rotational selection of “forced stroboscopic light-emitting mode”,“automatic flash mode”, “light-emitting inhibiting mode”, and the likeis executed according to the pushing-down numbers (initial setting is“light-emitting inhibiting mode”). Here, the key for setting astroboscopic light-emitting mode 60 has light emitting diodes (LEDs),and according to light-emitting modes, for example, switching-on of ared light (forced stroboscopic light-emitting mode), that of a bluelight (automatic flash mode), switching-off (light-emitting inhibitingmode), and the like are executed.

The flash driving unit 81 executes charging for a flash light (notshown), or switching-on of the flash light according to thelight-emitting modes set by operating the key for setting a stroboscopiclight-emitting mode 60 under control of the control unit 72, wherein theflash light is provided inside the stroboscopic light-emitting window 51on the front of the main body.

FIG. 16 is a flowchart showing one example of determining for one strokepressing and capturing operation of the shutter key 58 in the digitalcamera 50. This flowchart explains a program for realizing a function,by which the shutter is quickly fired, according to the embodiment ofthe present invention in the digital camera 50.

An example in which the control unit 72 basically executes the followingprocessing according to programs which are stored in a program memorysuch as a flash memory beforehand will be explained. However, not allthe functions are required to be stored in a program memory, and theremay be adopted a configuration in which a part of or all of programs arereceived through a network, if necessary, for executing the followingprocessing. Hereinafter, explanation will be made with reference toFIGS. 14A to 14C and 15.

When the main power supply of the digital camera 50 is turned into theON state, the control unit 72 sends a control signal to the flashdriving unit 81 to start charging for the flash light (step S1).Subsequently, AE processing for a through-image is executed by using afocal length corresponding to a zoom value at the time, and athrough-image is obtained from the CCD 63. At the same time, afteradjustment is made in the color processing circuit 68 in such a way thatwhite balance is made in accordance with the color of the light sourceby automatic white balance (AWB) processing (step S2), DMA transfer tothe DRAM 71 through the DMA controller 69 and the DRAM interface (I/F)70 is started. In addition, the VRAM 74 is rewritten by using videothrough-image data in which the image data from the CCD 63 is sampled,and a through-image is started to be displayed on the liquid-crystaldisplay screen 54 in the display device 76 (step S3).

When the control unit 72 examines a signal from the key input device 80(step S4), and the stroboscopic light-emitting setting key 10-2 isoperated, the processing proceeds to step S5, and when not pressed, theprocessing proceeds to step S6. When the stroboscopic light-emittingsetting key 10-2 is operated in step S4, stroboscopic light-emittingmode according to a set operation is set, a set value is kept in the RAM(step S5), and the processing proceeds to step S6.

When the control unit 72 examines a signal from the key input device 80,determines whether or not zooming operation with the zoom lever 57 isexecuted (step S6), and the zooming operation is performed, theprocessing proceeds to step S7, and when not performed, the processingproceeds to step S8. When the zooming operation is done in step S6, azoom value corresponding to the zooming operation is acquired, and anoptical zoom ratio is changed by driving the zoom driving unit 61-1based on this zoom value to move the zoom lens (step S7). At the sametime, the zoom value is stored into the RAM (overwritten), and theprocessing proceeds to step S8.

Subsequently, the control unit 72 examines a signal from the key inputdevice 80, and determines whether or not the shutter key 58 is halfpressed (step S8). When the shutter key is half pressed, the processingproceeds to step S9, and when not half pressed, the processing returnsto step S4.

When the shutter key 58 is half pressed in step S8, the control unit 72determines the stroboscopic light-emitting mode set in step S5 (stepS9). When it is determined that the surrounding brightness is equal toor smaller than a predetermined threshold under a state in which theforced stroboscopic light-emitting mode is set, or in which theautomatic flash mode is set, that is, when stroboscopic light-emittingis required, the processing is shifted to stroboscopic light capturingshown in the flowchart of FIG. 18. When not required, the processingproceeds to step S10.

When it is determined in step S9 that stroboscopic light-emitting is notrequired, the control unit 72 starts the AF processing of the contrastdetection type with a narrow step width for the image capturing, and, atthe same time, starts AE processing and automatic white balance (AWB)processing for the image capturing, based on the video through-imagedata captured at half pressing of the shutter key (step S10). Under theabove operations, the VRAM 74 is rewritten until the shutter key 58 isfully pressed by using video through-image data in which the image datafrom the CCD 63 is sampled, and a through-image is displayed on theliquid-crystal display screen 54 in the display device 76. In ordinaryAF processing of the contrast detection type, the AF driving unit 61-2moves the focus lens with uniform step intervals, the focus lens istemporarily stopped in each step to change the focus position frominfinite distance to this side, and contrast values are acquired andcompared. Finally, the focus lens is moved, assuming that a position atwhich the contrast value becomes the maximum is a focused position (stepS10).

Next, the control unit 72 examines the signal from the key input device80 to determine whether or not the shutter key is fully pressed, andwhen the shutter key 58 is fully pressed, the processing proceeds tostep S12 (step S11).

The control unit 72 determines whether or not the AF processing of thecontrast detection type is underway (step S12), when the AF processingis underway, the processing proceeds to step S13, and when not underway,the processing proceeds to step S14.

In AF processing of the contrast detection type (ordinary AF processing)for the image capturing, image data processing (capturing processing,contrast extraction processing, contrast comparison processing), anddriving control of the lens unit (moving, stopping of moving, andrestarting of moving) are required for every one step before determininga focused position. Further, there is required time between time atwhich a camera user catches a subject in a finder and time at which thesubject is in focus and a shutter button is fully pressed for imagecapturing. Accordingly, when the shutter key 58 is pressed at onestroke, simple AF processing with wide search intervals is configured tobe executed as shown in FIG. 17B. That is, when it is determined that AFprocessing is underway in step S12, the control unit 72 switches theprocessing to simple AF processing of the contrast detection type withstep widths wider than those of ordinary AF processing of the contrastdetection type, which is started by half pressing of the shutter key 58,and the simple AF processing of the contrast detection type is executed,following the ordinary AF processing of the contrast detection type.

In that case, referring to a corresponding table for simple AFprocessing (a corresponding table 90 between zoom values and searchintervals) as shown in FIG. 17A, the processing is switched to thesimple AF processing of the contrast detection type with wide stepwidths corresponding to the zoom values after the expression“full-pressing of the shutter key” shown in FIG. 17B. Here, FIG. 17B isa view showing focus positions at which the focus lens is temporarilystopped, and shows that moving of the focus lens is started in order toexecute ordinary AF processing of the contrast detection type from theend of the lens by half pressing of the shutter key 58, and theprocessing is switched to moving of the focus lens in order to executesimple AF processing of the contrast detection type from a position ofthe focus lens, at which the full-press of the shutter key 58 isdetected. In the example shown in FIGS. 17A and 17B, the search intervalpw₂=3 is obtained from FIG. 17A in the simple AF processing, assumingthat a zoom value=x₂ when the shutter key 58 is fully pressed, and thefocus lens is moved by three steps after a point at which the shutterkey 58 is fully pressed. Accordingly, the number of temporary stops ofthe focus lens becomes one thirds in the example shown in FIGS. 17A and17B when switching is made to the simple AF processing, so that themoving time of the focus lens is shortened, and the focusing time isshortened. That is, even if the moving range of the focus lens is thesame between the ordinary AF processing and the simple AF processing thesimple AF processing has the smaller number of temporary stops of thefocus lens (driving time of the focus lens), that of capturingoperations, that of acquiring the contrast data, and that of contrastdata comparing. Accordingly, the time between the operation of theshutter key 58 and that of capturing becomes shorter as a whole bycombining the ordinary AF processing and the simple AF processing (stepS13).

Moreover, the control unit 72 determines whether or not the AEprocessing for the image capturing, which is started in step S10, isunderway, the processing proceeds to step S15 when the AE processing isunderway, and the processing proceeds to step S16 when the AE processingis not underway (step S14).

The time lag at the shutter is affected not only by AF processing, butalso by AE processing. Therefore, switching is made to the simple AEprocessing when the shutter key 58 is fully pressed before the AEprocessing started by half pressing of the shutter key 58 is completed,that is, when the shutter key 58 is pressed at one stroke. Then, when itis determined in step S14 that the AE processing is underway, thecontrol unit 72 stops aperture control, which is one of AE processing,and subsequently, the processing proceeds to step S16. Thereby, theamount of AE processing is reduced, and the AE processing time isshortened. There may be adopted a configuration, as one modifiedexample, in which the aperture control is not stopped, but for example,omitting time-consuming operations is performed as simple AE processing(step S15).

Furthermore, the control unit 72 determines whether or not the automaticwhite balance (AWB) for the image capturing started in step S10 isunderway, the processing proceeds to step S17 when AWB is underway, andthe processing proceeds to step S18 when AWB is not underway (step S16).

The time lag at the shutter is effected not only by AF processing and AEprocessing, but also by AWB processing. Therefore, switching is made tothe simple AWB processing when the shutter key 58 is fully pressedbefore the AWB processing started by half pressing of the shutter key 58is completed, that is, when the shutter key 58 is pressed at one stroke.Then, when it is determined that the AWB processing is underway in stepS16, the processing proceeds to step S18 after switching is made to thesimple AWB processing by the control unit 72. Thereby, the amount of AWBoperation is reduced, and the AWB operation time is shortened. Here, thewhite balance (WB) value of a suitable pattern which has been selectedfrom, ordinarily, about seven patterns is used in the AWB processing.However, the WB value of a suitable pattern which has been selectedfrom, for example, about three typical patterns is used in simple AWBprocessing (step S17).

The control unit 72 determines whether or not all the processing, thatis, processing in steps S10, S13, or S17, that is, all the processing ofthe AF processing, the AE processing, and the AWB processing arecompleted. The processing proceeds to step S19 when completed, and thecompletion is waited when not completed (step S18). Immediately afterall the processing is completed, the path from CCD 63 to the DRAM 71 isinterrupted at this point and switching is made to a CCD drive methodfor the image capturing different from the method used for acquiring athrough-image. After image compressing processing of the captured imagedata, this compressed image data (image file) is recorded to completecapturing of the image for one frame, and the processing returns to stepS2 (step S19).

FIGS. 17A and 17B are views each explaining the corresponding table 90for simple AF processing, in which the zoom values referred by theimage-forming program and the search intervals of the focus lens areassociated. The FIG. 17A is a configuration example for thecorresponding table 90, and FIG. 17B is a view explaining the simple AFprocessing using the corresponding table 90.

In the corresponding table 90, zoom values x₁, x₂, . . . , x_(n) are setfrom the telephoto side to the wide-angle side, and each of the zoomvalues is corresponding, as shown in FIG. 17A, to the search intervalspw₁, pw₂, . . . for simple AF processing, respectively. In ordinary AFprocessing (the first AF processing), the search intervals are the sameas one another as shown in FIG. 17B. However, the simple AF processing(the second AF processing) has a configuration in which step widths aredifferent from one another according to the zoom values, and the movingwidth (step width) of the focus lens when the zoom lens is at thetelephoto side is shorter than step width when the focus lens is at thewide-angle side.

The search intervals of the corresponding table 90 are set according tothe zoom values, in such a way that the search interval pw₁ is set twosteps when the zoom value is x₁, and the search interval pw₂ is setthree steps when the zoom value is x₂, for example, assuming that thetelephoto side is set on the left, and the wide angle side is set on thelight in FIG. 17A. Accordingly, the stopping number is reduced in such away that the stopping number of the focus lens when the zoom value is x₁is half the ordinary AF processing, and the stopping number of the focuslens when the zoom value is x₃ is one third the ordinary AF processing,. . . . Therefore, the lens moving time is shortened, and furthermore,time for acquiring contrast values, time for comparing contrast values,capturing time are shortened. As a whole, time between full-press of theshutter key 58 and capturing is shortened in the simple AF processing inwhich the corresponding table 90 setting the search intervals as shownin FIGS. 17A and 17B.

It is assumed in this example that such point data for focusing everyzoom steps is stored as table constants and the like in the programstorage memory, and is referred to at operation of the image-formingprogram shown in the flowchart, and the like of FIG. 16. Here, there maybe adopted a configuration in which the point data is set in the storagememory 78, and is referred to by the image-capturing program.

Capturing with Strobe Light

FIG. 18 is a flowchart showing one example for determination ofone-stroke pressing of the shutter key 58 and capturing in the digitalcamera 50 when the forced stroboscopic light-emitting mode (or when itis determined that the stroboscopic light-emitting is required in theautomatic flash mode) is selected. The drawing shows one example of thecapturing operation of the digital camera 50 when it is determined thatstroboscopic light-emitting is required in determination processing instep S9 of the flowchart shown in FIG. 16.

When it is determined that the stroboscopic light-emitting is requiredin step S9 in the flowchart of FIG. 16, the control unit 72 starts theAF processing of the contrast detection type for the stroboscopic lightcapturing processing, and, at the same time, WB (white balance) valuesand exposure (EV) values for stroboscopic light capturing are set (stepS21). Under the above operations, the through-image is displayed on theliquid-crystal display screen 54 until the shutter key 58 is fullypressed.

Next, the control unit 72 examines the signal from the key input device80 to determine whether or not the shutter key 58 is fully pressed (stepS22), and when the shutter key 58 is fully pressed, the processingproceeds to step S23.

The control unit 72 determines whether or not the AF processing of thecontrast detection type is underway (step S23). The processing proceedsto step S24 when the AF processing is underway, and the processingproceeds to step S26 when not underway.

Since the time lag at the shutter is affected by AF processing,switching is made to the simple AF processing when the shutter key 58 isfully pressed before the AF processing started by half pressing of theshutter key 58 is completed, that is, when the shutter key 58 is pressedat one stroke. Then, the processing proceeds to step S25 after thecontrol unit 72 switches the AF processing under execution to the simpleAF processing in which the corresponding table 90 for simple AFprocessing shown in FIG. 17A is referred to when it is determined thatAF processing is underway in step S23 (step S24).

The control unit 72 determines whether or not the simple AF processingis completed, and the processing proceeds to step S26 (step S25) whenthe simple AF processing is completed. Then, it is determined whether ornot charging for the flash light is underway (step S26). The processingproceeds to step S27 when underway, and the processing proceeds to stepS28 when not underway.

Since not only AF processing, but also stroboscopic light charging isalso one of factors for longer time lag in the shutter, capturing isconfigured to be performed based on shutter-priority operation when theshutter key 58 is fully pressed under stroboscopic light charging. Then,the control unit 72 stops the stroboscopic light charging (step S27)when it is determined in step S26 that the stroboscopic light chargingis underway, and the flash light is emitted by controlling the flashdriving unit 81. At that time, the path from the CCD 63 to the DRAM 71is immediately interrupted at that time, and switching is made to a CCDdrive method for the image capturing different from the method used foracquiring a through-image. After image compressing processing of thecaptured image data, this compressed image data (image file) is recordedto complete capturing of the image for one frame (step S28), and theprocessing returns to step S1 of FIG. 16. Here, when the flash lightcharge is stopped in step S27, light emitting of the flash light isrealized with a light-emitting amount within a capacity under chargingin step S28.

When the shutter key 58 is half pressed by operations shown in theflowchart of FIG. 16, the AF processing, the AE processing, the AWBprocessing are started. When the shutter key 58 is fully pressed underhalf pressing, the AF processing, the AE processing, and the AWBprocessing are switched to the simple AF processing, the AE processing,and the AWB processing. Accordingly, the processing time can beshortened, and time between a point at which the shutter key 58 is fullypressed and the image capturing can be shortened. Consequently,miss-releasing of the shutter, and generation of the time lag can beprevented. An image with good focusing accuracy can be obtained withright-time firing of the shutter and without generating time lag.Moreover, since capturing is performed without eliminating the AFprocessing even if the shutter key 58 is fully pressed, an image withgood focusing accuracy can be captured without using a lens with acertain degree of deep depth-of-field.

The time lag at the shutter is effected by, for example, AF processing,so that the processing is executed based on shutter priority operationeven under the AF processing when the shutter key 58 is pressed at onestroke. Accordingly, the focusing accuracy is more improved by capturingaccording to the simple AF processing (refer to step S13) in comparisonwith a case in which capturing is made under stopping the AF processing,and the AF time can be more extremely shortened in comparison with acase in which capturing is made after completing the AF processing.

Moreover, the time lag at the shutter is affected by AE processing.Therefore, when the shutter key 58 is pressed at one stroke, theprocessing is executed based on shutter priority operation. The AEprocessing is performed at any moment during preparation operation forcapturing even in a configuration in which the simple AE processing isperformed for capturing, following normal AE operations (refer to stepS15). Accordingly, opportunity for wrong exposure is reduced at actualcapturing, different from focusing operation in which AF processing isperformed for the first time at half pressing of the shutter key 58.Moreover, post correction can be easily realized by using a program fora retouched photo, and the like even if capturing is made withinsufficient AE processing (under or over exposure).

Moreover, since the time lag at the shutter is affected by AWBprocessing, so that, when the shutter key 58 is pressed at one stroke,the processing is executed based on shutter priority operation. The AWBprocessing is performed at any moment during preparation operation forcapturing even in a configuration in which the simple AWB processing isperformed for capturing, following normal AWB operations (refer to stepS17). Accordingly, opportunity for wrong determination is reduced.Moreover, post correction can be easily realized by using a program fora retouched photo, and the like even if capturing is made with incorrectAWB processing (wrong coloration).

Furthermore, according to operations shown in the flowchart of FIG. 18,charging for flash light is stopped in the digital camera 50 when theshutter key 58 is fully pressed. For this reason, time between a pointat which the shutter key 58 is fully pressed and stroboscopic lightcapturing is made shorter, so that capturing can be made with right-timefiring of the shutter and without generating time lag.

MODIFIED EXAMPLES OF THE THIRD EMBODIMENT

According to the flowchart shown in FIGS. 16 and 18, switching is madeto the simple processing under a determining condition for one-strokepressing that, when the shutter key 58 is fully pressed under a state inwhich AF processing is underway after half pressing of the shutter key58, that is, when the shutter key 58 is fully pressed, the processing isunder AF processing, under AE processing, and under AWB processing. But,a method for pressing of the shutter key 58 at one stroke is not limitedto the above method. Hereinafter, a modified example of determinationfor one stroke pressing of the shutter key 58 will be described.

FIG. 19 is a flowchart showing a modified example for determination ofone-stroke pressing of the shutter key 58 and capturing in the digitalcamera. The modified example has a configuration in which half-pressoperation is not started unless the half-press of the shutter key 58 iskept for a predetermined time or longer, and steps after step S8 in theflowchart shown in FIG. 16 are changed to steps S30 through S42 as shownin FIG. 19. According to step S30 through step S33 in FIG. 19, it isdetermined that, when the shutter key 58 is fully pressed within apredetermined time after the shutter key is half pressed, the shutterkey 58 is pressed at one stroke, and the processing is shifted to simpleprocessing based on steps S34 through S42.

In FIG. 19, when zooming operation is not performed in step S6 in FIG.16, or when the zooming ratio is changed according to zooming operationsin step S7 in FIG. 16, the control unit 72 determines, based on a signalfrom the key input device 80, whether or not the shutter key 58 has beenhalf pressed (step S30). When the shutter key 58 has been half pressed,the processing proceeds to step S31, and when not half pressed, theprocessing returns to step S4 in the flowchart of FIG. 16.

The control unit 72 starts a measuring timer for shutter operating timeafter zero clearance of the timer (step S31). When time is up, that is,when a predetermined time has passed (full-pressing is not performedwithin a predetermined time after half pressing is done) (Yes in stepS32), it is determined that a user has intended to perform half pressingoperation, and the processing proceeds to step S9 in the flowchart ofFIG. 16 to start half pressing (S10 through S19, or S21 through S28).When the time is within the predetermined time (No in step S32), theprocessing proceeds to step S33.

Then, the control unit 72 examines the signal from the key input device80 to determine whether or not the shutter key 58 is fully pressed (stepS33), and when the shutter key 58 is fully pressed, the processingproceeds to step S34. When the shutter key 58 is not fully pressed, theprocessing returns to step S32.

When the shutter key 58 is pressed at one stroke during steps S31through S33 (full-pressing is performed within the predetermined timeafter half pressing is done), the control unit 72 examines thestroboscopic light-emitting mode set in step S5 in the flowchart of FIG.16 (step S34). In the case of a mode in which the forced stroboscopiclight-emitting mode, or the stroboscopic light-emitting mode is required(Yes in step S34), the processing proceeds to step S38, and in the caseof a mode in which the forced stroboscopic light-emitting mode, or thestroboscopic light-emitting mode is not required (No in step S34), theprocessing proceeds to step S35.

When it is determined that the stroboscopic light-emitting is notrequired in step S34, the control unit 72 starts simple AF processing ofthe contrast detection type (for example, AF processing by referring tothe corresponding table 90 for simple AF processing as shown in FIG.17A) for the image capturing (step S35). At the same time, AE processingand automatic white balance (AWB) processing are started based on thevideo through-image data captured at half pressing of the shutter key58.

The control unit 72 determines whether or not all the processing, thatis, the simple AF processing, the AE processing, and the AWB processing,which have started in step S35, are completed (step S36). The processingproceeds to step S37 when completed, and the completion is waited whennot completed. When all the processing is completed, the path from theCCD 63 to the DRAM 71 is immediately interrupted at that time, andswitching is made to a CCD drive method for the image capturingdifferent from the method used for acquiring a through-image. Afterimage compressing processing of the captured image data, this compressedimage data (image file) is recorded to complete capturing of the imagefor one frame, and the processing returns to step S2 (step S37).

When it is determined in step S34 that the stroboscopic light-emittingis required, the control unit 72 starts the above-described simple AFprocessing after setting WB (white balance) values and exposure (EV)values for stroboscopic light capturing (step S38).

The control unit 72 determines whether or not the simple AF processingis completed (step S39). The processing proceeds to step S40 when thesimple AF processing is completed. Then, it is determined whether or notcharging for the flash light is underway (step S40). The processingproceeds to step S41 when underway, and when not underway, theprocessing proceeds to step S42.

The control unit 72 stops the stroboscopic light charging (step S41)when it is determined in step S40 that the stroboscopic light chargingis underway. The flash light is emitted within the allowable capacityfor the strobe light at the current time (step S42). At the same time,the path from the CCD 63 to the DRAM 71 is immediately interrupted atthat time, and switching is made to a CCD drive method for the imagecapturing different from the method used for capturing a through-image.After image compressing processing of the captured image data, thiscompressed image data (image file) is recorded to complete capturing ofthe image for one frame, and the processing returns to step S1.

According to operations shown in the flowchart of FIG. 19, it isdetermined that the shutter key 58 is pressed at one stroke when theshutter key 58 is fully pressed within a predetermined time after theshutter key 58 is half pressed, and capturing for the image capturing isexecuted according to simple AF processing, AE processing, and AWBprocessing. Accordingly, the time between a point at which the shutterkey 58 is pressed at one stroke and the image capturing can be shortenedto extremely shorter one, and an image with good focusing accuracy canbe obtained with right-time firing of the shutter and without generatingtime lag. Moreover, when the stroboscopic light capturing is required,the stroboscopic light charging is stopped for the stroboscopic lightcapturing. Accordingly, the time between a point at which the shutterkey is pressed at one stroke and the image capturing can be shortened toextremely shorter one, and the similar advantages to those of theabove-described example can be obtained.

In the above described modified example, it has been determined that,when the shutter key 58 is fully pressed within a predetermined timeafter the shutter key 58 is half pressed, the shutter key 58 is pressedat one stroke, a method for determining the one-stroke pressing of theshutter key is not limited to the above one. There may be adopted aconfiguration in which half-press operation is not started unless thehalf-press of the shutter key 58 is kept for equal to or longer thanpredetermined time. That is, there may be adopted a configuration inwhich, when it is determined in step S30 in FIG. 19 that the shutter key58 is half pressed, AF processing of the contrast detection type forimage capturing, AE processing, and, the AWB processing are executed;and, in the other cases (when the shutter key 58 is not half pressed),it is determined in the case of full-press that the shutter key 58 ispressed at one stroke, and the processing is shifted to processing insteps S33 through S42 in FIG. 19. Even in the above configuration, it isdetermined that, when the shutter key 58 is fully pressed within apredetermined time after operation of the shutter key 58, the shutterkey 58 is pressed at one stroke. Then, capturing for the image capturingis executed according to simple AF processing, AE processing, and AWBprocessing. Accordingly, the time between a point at which the shutterkey 58 is pressed at one stroke and the image capturing can be shortenedto extremely shorter one, and the similar advantages to those of theabove-described modified example can be obtained.

Moreover, there may be adopted another configuration as follows. Thatis, by installing a shutter key 58 by which the half-press operation cannot be electrically detected (recognized) unless the half-pressoperation is kept for a predetermined time, and, by repeateddetermination on whether or not the shutter key 58 is fully pressed, orwhether or not the shutter key 58 is half pressed, it is determined thatone-stroke pressing is caused when it is determined withoutdetermination in which the shutter key is half pressed that the shutterkey 58 is fully pressed (that is, when the shutter key 58 is fullypressed at one stroke, and when the shutter key 58 passes through ahalf-press position for a moment) and, then, the processing is shiftedto processing in steps S33 through S42 in FIG. 19. Even in the aboveconfiguration, capturing for the image capturing is executed accordingto simple AF processing, AE processing, and AWB processing. Accordingly,the time between a point at which the shutter key 58 is pressed at onestroke and the image capturing can be shortened to extremely shorterone, and the similar advantages to those of the above-described modifiedexample can be obtained.

Fourth Embodiment

The third embodiment has a configuration in which switching is made tosimple processing in such a way that AF processing, AE processing, AWBprocessing, stroboscopic light-emitting, and the like are easilyperformed when a shutter key 58 is pressed at one stroke, so that timefrom the shutter operation to the capturing processing is shortened.However, a method by which time between shutter operation and capturingprocessing can be shortened is not limited to the examples according tothe third embodiment.

Hereinafter, examples in which, when the shutter key 58 is pressed atone stroke, AF processing, AE processing, AWB processing, stroboscopiclight-emitting, and the like are stopped (or, are not performed), andtime between shutter operation and capturing processing can beshortened, will be described. Here, it is assumed in the followingexplanation that the appearance and an internal configuration of adigital camera are similar to those of the digital camera 50 shown inFIGS. 14A to 14C and 15.

FIG. 20 is a flowchart showing one example for capturing operation basedon one-stroke pressing of the shutter key 58 in the digital camera 50.This flowchart explains a program for realizing a function, by which theshutter is quickly fired, according to the present invention in thedigital camera 50.

Examples in which the control unit 72 basically executes the followingprocessing according to programs stored in a program memory such as aflush memory beforehand will be explained. However, there may be adopteda configuration in which all the functions are not required to be storedin the program memory, and a part of or all of the functions arereceived through a network, as necessary. Hereinafter, explanation willbe made, referring to FIGS. 13, 14A to 14C, and 20. Here, processing insteps S1 through S7 in FIG. 20 is similar to that of steps S1 through S7in FIG. 16.

In FIG. 20, a control unit 72 examines in step S61 stroboscopiclight-emitting mode set in step S5 when the shutter key 58 is halfpressed in step S8 (FIG. 16). Then, in the case of a mode such as forcedstroboscopic light-emitting mode and automatic flash mode requiringstroboscopic light-emitting, the processing proceeds to step S67; and,in the case of another mode with no requirements, the processingproceeds to step S62.

When it is determined that the stroboscopic light-emitting is notrequired in step S61, the control unit 72 starts AF processing of thecontrast detection type for the image capturing, and at the same time,the AE processing and the AWB processing, based on video through-imagedata captured when the shutter 58 is half pressed (step s62). Under theabove operations, the VRAM 74 is rewritten until the shutter key 58 isfully pressed by using video through-image data in which the image datafrom the CCD 63 is sampled, and a through-image is displayed on theliquid-crystal display screen 54 in the display device 76.

Subsequently, the control unit 72 examines in step S63 the signal fromthe key input device 80 to determine whether or not the shutter key 58is fully pressed. When the shutter key 58 is fully pressed, theprocessing proceeds to step S64.

In step S64, the control unit 72 determines whether or not any one ofthe AF, the AE or the AWB processing, which have been started in stepS62, is still underway (step S64). Then, when no processing is underway,the processing proceeds to step S66, and when any one of the processingis underway, operation under processing is stopped in step S65. In stepS66, the path from the CCD 63 to the DRAM 71 is immediately interrupted,and switching is made to a CCD drive method for the image capturingdifferent from the method used for capturing a through-image. Afterimage compressing processing of the captured image data, this compressedimage data (image file) is recorded to complete capturing of the imagefor one frame, and the processing returns to step S2.

Moreover, when it is determined that stroboscopic light-emitting isrequired in step S61, the control unit 72 starts AF processing of thecontrast detection type for stroboscopic light capturing, and, at thesame time, WB (white balance) values and exposure (EV) values forstroboscopic light capturing are set (step S67). Under the aboveoperations, a through-image is displayed on the liquid-crystal displayscreen 54 until the shutter key 58 is fully pressed.

Next, the control unit 72 examines in step S68 the signal from the keyinput device 80 to determine whether or not the shutter key 58 is fullypressed. When the shutter key 58 is fully pressed, the processingproceeds to step S69.

The control unit 72 determines in step S69 whether or not AF processingof the contrast detection type which has been started in step S67 isunderway. When the AF processing is underway, the processing proceeds tostep S70, and when not underway, the processing proceeds to step S71.

When it is determined in step S69 that the AF processing is underway,the control unit 72 stops the AF processing (step S70), and theprocessing proceeds to step S71. Furthermore, it is determined in stepS71 whether or not the stroboscopic light charging is underway. When thecharging is underway, the processing proceeds to step S72, and when notunderway, the processing proceeds to step S74.

When it is determined in step S71 that the stroboscopic light chargingis underway, the stroboscopic light charging is stopped (step S72) withno stroboscopic light-emitting. In step S73, the path from the CCD 63 tothe DRAM 71 is immediately interrupted, and switching is made to a CCDdrive method for the image capturing different from the method used forcapturing a through-image. After image compressing processing of thecaptured image data, this compressed image data (image file) is recordedto complete capturing of the image for one frame, and the processingreturns to step S1.

When it is determined in step S71 that the stroboscopic light chargingis not underway, the flash light is emitted by controlling the flashdriving unit 81 (step S74). At that time, the path from the CCD 63 tothe DRAM 71 is immediately interrupted, and switching is made to a CCDdrive method for the image capturing different from the method used forcapturing a through-image. After image compressing processing of thecaptured image data, this compressed image data (image file) is recordedto complete capturing of the image for one frame, and the processingreturns to step S1.

According to the flowchart of FIG. 20, when the shutter key 58 is halfpressed, AF processing, AE processing, AWB processing are started aspreparation operation for capturing. When the shutter key is fullypressed during half-press, the preparation operation for capturing underprocessing is stopped and the capturing operation is started.Accordingly, when the shutter key 58 is fully pressed, image capturingcan be performed for a moment. Thereby, an image can be captured withright-time firing of the shutter and without generating time lag.Moreover, since the stroboscopic light charging is stopped for capturingeven when stroboscopic light charging is underway, the similaradvantages can be obtained.

MODIFIED EXAMPLE

According to the flowchart shown in FIG. 20, processing under operationis stopped under a determining condition for one-stroke pressing that,when the shutter key 58 is fully pressed under a state in which AFprocessing is underway after half pressing of the shutter key 58, thatis, when the shutter key 58 is fully pressed, the processing is under AFprocessing, under AE processing, and under a state in which the AWBprocessing is not completed. But, a method for pressing of the shutterkey 58 at one stroke is not limited to the above method, and similarmethods for pressing of the shutter key at one stroke to those of themodified example of the third embodiment. Hereinafter, a modifiedexample of determination for one stroke pressing of the shutter key 58will be described.

FIG. 21 is a flowchart showing a modified example for determination ofone-stroke pressing of the shutter key 58 and capturing in the digitalcamera. The modified example has a configuration in which half-pressoperation is not started unless the half-press of the shutter key 58 iskept for equal to or longer than predetermined time, and steps afterstep S31 in the flowchart shown in FIG. 19 are changed to steps S80through S89 as shown in FIG. 21. Thereby, when the shutter key 58 isfully pressed within a predetermined time after the shutter key 58 ishalf pressed in step 30 in FIG. 19, it is determined that the shutterkey 58 is pressed at one stroke, and the processing is shifted toprocessing in steps S82 through S89 processing.

In FIG. 21, a measuring timer for shutter operating time is startedafter zero clearance of the timer in step S31 in FIG. 19. When time isup (Yes in step S80), that is, when a predetermined time has passed(full-pressing is not performed within a predetermined time after halfpressing is done), it is determined that a user has intended to performhalf pressing operation, and the processing proceeds to step S61 in theflowchart of FIG. 20 to start half pressing (S61 through S74). When thefull-pressing is performed within the predetermined time (No in stepS80), the processing proceeds to step S81.

Subsequently, the control unit 72 examines the signal from the key inputdevice 80 to determine whether or not the shutter key 58 is fullypressed (step S81). When the shutter key 58 is fully pressed within thepredetermined time, it is determined that the shutter 58 is pressed atone stroke, and the processing proceeds to step S82. When the shutterkey 58 is not fully pressed within the predetermined time, theprocessing returns to step S80.

When the shutter key 58 is pressed at one stroke in steps S80 and S81(full-pressing is performed within the predetermined time after halfpressing is done), the control unit 72 examines in step S82 thestroboscopic light-emitting mode set in step S5 (in the flowchart ofFIG. 16). In the case of a mode such as forced stroboscopiclight-emitting mode and automatic flash mode requiring stroboscopiclight-emitting (Yes in step S82), the processing proceeds to step S85,and in the case of another mode with no requirements (No in step S82),the processing proceeds to step S83.

When it is determined in step S82 that stroboscopic light-emitting isnot required, the control unit 72 stops the AE processing and the AWBprocessing for a through-image (step S83). At that time, the path fromthe CCD 63 to the DRAM 71 is immediately interrupted, and switching ismade to a CCD drive method for the image capturing different from themethod used for capturing a through-image. After image compressingprocessing of the captured image data, this compressed image data (imagefile) is recorded to complete capturing of the image for one frame (stepS84), and the processing returns to step S2 (in the flowchart in FIG.16).

When it is determined that stroboscopic light-emitting is required instep S82, the control unit 72 sets WB (white balance) values andexposure (EV) values for stroboscopic light capturing (step S85), and itis determined whether or not the stroboscopic light charging is underway(step S85). When the charging is underway, the processing proceeds tostep S87, and when not underway, the processing proceeds to step S89.

When it is determined in step S86 that stroboscopic light charging isunderway, the stroboscopic light charging is stopped with nostroboscopic light-emitting (step S87). At that time, the path from theCCD 63 to the DRAM 71 is immediately interrupted, and switching is madeto a CCD drive method for the image capturing different from the methodused for capturing a through-image. After image compressing processingof the captured image data, this compressed image data (image file) isrecorded to complete capturing of the image for one frame (step S88),and the processing returns to step S1.

On the other hand, when it is determined in step S86 that stroboscopiclight charging is not underway, the flash light is emitted (step S89).At that time, the path from the CCD 63 to the DRAM 71 is immediatelyinterrupted, and switching is made to a CCD drive method for the imagecapturing different from the method used for capturing a through-image.After image compressing processing of the captured image data, thiscompressed image data (image file) is recorded to complete capturing ofthe image for one frame (step S89), and the processing returns to stepS1.

According to operations shown in the flowchart of FIG. 21, it isdetermined that the shutter key 58 is pressed at one stroke when theshutter key 58 is fully pressed within a predetermined time after theshutter key 58 is half pressed, and capturing is executed withoutexecuting AF processing, AE processing, and AWB processing for the imagecapturing. Accordingly, when the shutter key 58 is fully pressed,capturing can be executed for a moment. Thereby, an image can becaptured with right-time firing of the shutter and without generatingtime lag. Moreover, since the stroboscopic light charging is stopped,and capturing is performed without flash light when stroboscopic lightcharging is underway under a state in which stroboscopic light capturingis required, the similar advantages can be obtained.

In the above-described modified example, it has been determined that,when the shutter key 58 is fully pressed within a predetermined timeafter the shutter key 58 is half pressed, the shutter key 58 is pressedat one stroke. However, a method for determining the one-stroke pressingof the shutter key is not limited to the above one. There may be adopteda configuration in which half-press operation is not started unless thehalf-press of the shutter key 58 is kept for equal to or longer thanpredetermined time. That is, there may be adopted a configuration inwhich, when it is determined in step S30 in FIG. 19 that the shutter key58 is half pressed, AF processing of the contrast detection type forimage capturing, AE processing, and, the AWB processing are executed;and, in the other cases (when the shutter key 58 is not half pressed),it is determined in the case of full-press that the shutter key 58 ispressed at one stroke, and the processing is shifted to processing insteps S82 through S89 in FIG. 21. Even in the above configuration, it isdetermined that, when the shutter key 58 is fully pressed within apredetermined time after operation of the shutter key 58, the shutterkey 58 is pressed at one stroke, and capturing is executed after AFprocessing, AE processing, and AWB processing are stopped. Accordingly,time between a point of shutter operation and image capturing can beshortened to extremely shorter one, and the similar advantages to thoseof the above-described modified example can be obtained.

Moreover, there may be adopted another configuration in which, byinstalling a shutter key 58 by which the half-press operation can not beelectrically detected (recognized) unless the half-press operation iskept for a predetermined time, and, by repeated determination on whetherthe shutter key 58 is fully pressed or the shutter key 58 is halfpressed, it is determined that one-stroke pressing is caused when it isdetermined without determination in which the shutter key is halfpressed that the shutter key 58 is fully pressed (that is, when theshutter key 58 is fully pressed at one stroke, and when the shutter key58 passes through a half-press position for a moment) and, then, theprocessing is shifted to processing in steps S33 through S42 in FIG. 19.Even the above configuration, capturing is executed after AF processing,AE processing, and AWB processing are stopped. Accordingly, time betweena point of shutter operation and image capturing can be reduced toextremely shorter one, and the similar advantages to those of theabove-described modified example can be obtained.

Moreover, the third and fourth embodiments, and the modified examplesthereof have a configuration in which AF operation started by halfpressing of the shutter key 58 and AF operation started by full-pressingof the shutter key 58 have the same AF search range. But, there may beadopted a configuration in which both the AF operations have differentAF search ranges from each other. There may be adopted a configuration,for example, in which, assuming that the AF search range for the AFoperation started by half pressing of the shutter key 58 is a first AFsearch range, and the AF search range for AF operation started byfull-pressing of the shutter key 58 is a second AF search range, thesecond AF search range is narrower than the first AF search range. Inthe above case, the second AF search range may be configured toarbitrarily be set by manual operation of a user, or a capturing sceneis determined based on captured conditions acquired at capturing andcontrast values acquired from image data and the an AF search rangecorresponding to the determined result may be configured to be thesecond AF search range.

In the explanation for the third and fourth embodiments, the searchinterval of the focus lens at simple AF processing has been set at avalue (a fixed value) which has been set beforehand, according to zoomvalues as shown in the example of FIG. 17A. But, the search interval ofthe focus lens may be configured to be set by manual corresponding tothe zoom values, or the search interval of the focus lens may beconfigured to automatically be set corresponding to the zoom values, andbased on captured conditions acquired at capturing and contrast valuesacquired from image data.

Furthermore, the fourth embodiment has a configuration in which allkinds of AF processing such as stopping processing of the focus lens,capturing processing, contrast-data acquisition processing, andcontrast-data comparison processing are simplified when the shutter key58 is fully pressed. But, there may be adopted a configuration in whichany one of stopping processing of the focus lens, capturing processing,contrast-data acquisition processing, and contrast-data comparisonprocessing is simplified, for example, only contrast-data comparisonprocessing is simplified, or a configuration in which only thecontrast-data comparison processing; only a combination of thecontrast-data acquisition processing and the contrast-data comparisonprocessing; only a combination of the capturing processing, thecontrast-data acquisition processing, and the contrast-data comparisonprocessing; or a combination of stopping processing of the focus lens,capturing processing, contrast-data acquisition processing, andcontrast-data comparison processing is simplified.

While the description above refers to particular embodiments of thepresent invention, it will be understood that many modifications may bemade without departing from the spirit thereof. The accompanying claimsare intended to cover such modifications as would fall within the truescope and spirit of the present invention. The presently disclosedembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims, rather than the foregoing description,and all changes that come within the meaning and range of equivalency ofthe claims are therefore intended to be embraced therein. For example,the digital camera has been used as a camera in the explanation forexamples. The term “camera” can be applied to a cellular telephone witha camera function, information-processing equipment with a camerafunction, and the like, other than an image capture device such as adigital camera.

1. An image capture device comprising: automatic-focusing means forcomparing contrast values of captured images which are sequentiallyobtained through an image capture element while moving a focus lens andfor detecting a focused lens position of the focus lens based on resultsof comparisons; a shutter button which is able to be half pressed andfully pressed; first determining means for determining whether or notthe shutter button is half pressed; second determining means fordetermining whether or not the shutter button is fully pressed; firstautomatic-focus control means for, when the first determining meansdetermines that the shutter button is half pressed, executing a firstautomatic-focusing processing by using the automatic-focusing means; andsecond automatic-focus control means for, when the second determiningmeans determines that the shutter button is fully pressed, executing asecond automatic-focusing processing with higher processing speed thanthat of the first automatic-focusing processing by using theautomatic-focusing means.
 2. The image capture device according to claim1, wherein the first automatic-focus control means includes means for,when the first automatic-focusing processing is executed, comparingcontrast values of the captured images obtained through the imagecapture element at each focus-lens position which is specified based ona first lens-position interval, and the second automatic-focus controlmeans includes means for, when the second automatic-focusing processingis executed, comparing contrast values of the captured images obtainedthrough the image capture element at each focus-lens position which isspecified with a second lens-position interval wider than the firstlens-position interval.
 3. The image capture device according to claim2, further comprising: optical zoom-ratio setting means for setting anoptical zoom-ratio; and optical zooming means for moving the zoom lens,based on the optical zoom-ratio set by the optical zoom-ratio settingmeans, and wherein the second automatic-focus control means includesmeans for, when the second automatic-focusing processing is executed,comparing contrast values of the captured images obtained through theimage capture element at each focus-lens position which is specifiedwith a second lens-position interval corresponding to an opticalzoom-ratio set by the optical zoom-ratio setting means.
 4. The imagecapture device according to claim 2, wherein the first automatic-focuscontrol means includes means for detecting the contrast values at eachfocus lens-position which is specified based on the first lens-positioninterval, and the second automatic-focus control means includes meansfor detecting the contrast values at each focus lens-position which isspecified based on the second lens-position interval.
 5. The imagecapture device according to claim 4, wherein the first automatic-focuscontrol means includes means for acquiring captured images by drivingthe image capture element with the first lens-position interval; and thesecond automatic-focus control means includes means for acquiringcaptured images by driving the image capture element with the secondlens-position interval.
 6. The image capture device according to claim5, wherein the first automatic-focus control means includes means fortemporarily stopping the focus lens with the first lens-positioninterval, and for acquiring captured images by driving the image captureelement at temporary stops, and the second automatic-focus control meansincludes means for temporarily stopping the focus lens with the secondlens-position interval, and for acquiring captured images by driving theimage capture element at temporary stops.
 7. The image capture deviceaccording to claim 1, wherein the first automatic-focus control meansincludes means for moving the focus lens at a first speed, and thesecond automatic-focus control means includes means for moving the focuslens at a second speed higher than the first speed.
 8. The image capturedevice according to claim 1, wherein the first automatic-focus controlmeans includes means for sequentially obtaining captured images bydriving the image capture element at a first frame rate, and the secondautomatic-focus control means includes means for sequentially obtainingcaptured images by driving the image capture element at a second framerate higher than the first frame rate.
 9. The image capture deviceaccording to claim 1, wherein the first automatic-focus control meansincludes means for obtaining captured images by exposing the imagecapture element for a first exposure time, and the secondautomatic-focus control means includes means for obtaining capturedimages by exposing the image capture element for a second exposure timeshorter than the first exposure time.
 10. The image capture deviceaccording to claim 1, wherein the first automatic-focus control meansincludes means for moving the focus lens in a first moving range, andthe second automatic-focus control means includes means for moving thefocus lens in a second moving range narrower than the first movingrange.
 11. The image capture device according to claim 1, wherein thefirst automatic-focus control means includes: detecting means for, whenthe first automatic-focusing processing is executed, comparing contrastvalues of the captured images obtained through the image capture elementat each focus-lens position which is specified with a firstlens-position interval, and detecting a focused lens position based onresults of comparisons; and means for comparing contrast values of thecaptured images obtained through the image capture element while movingthe focus lens in the vicinity of the focused position detected by thedetecting means at each focus-lens position which is specified with asecond lens-position interval narrower than the first lens-positioninterval, and for setting the focused lens position which is detectedbased on the results of the comparisons to the focused lens position ofthe focus lens, and the second automatic-focus control means includesmeans for, when the second automatic-focusing processing is executed,comparing contrast values of the captured images obtained through theimage capture element at each focus-lens position which is specifiedwith the first lens-position interval, and for setting the focused lensposition which is detected based on the results of the comparison to thefocused lens position of the focus lens.
 12. The image capture deviceaccording to claim 1, further comprising: third determining means for,when the second determining means determines that the shutter button isfully pressed, determining whether or not the first automatic-focusingprocessing is executed by the first automatic-focus control means, andwherein the second automatic-focus control means includes means for,when the third determining means determines that the firstautomatic-focusing processing is executed, executing the secondautomatic-focusing processing following the first automatic-focusingprocessing, and detecting the focused lens position of the focus lensbased on results of the first and second automatic-focusing processings.13. The image capture device according to claim 1, further comprising:third determining means for, when the second determining meansdetermines that the shutter button is fully pressed, determining whetheror not the first automatic-focusing processing is executed by the firstautomatic-focus control means, and fourth determining means for, whenthe third determining means determines that the first automatic-focusingprocessing is executed, determining whether or not a first predictedtime necessary for detecting the focused lens position of the focus lensfor a case in which the first automatic-focusing processing iscontinuously executed by the first automatic-focus control means isshorter than a second predicted time necessary for detecting the focusedlens position of the focus lens for a case in which the secondautomatic-focusing processing is executed, and wherein the firstautomatic-focus control means includes means for, when the fourthdetermining means determines that the first predicted time is shorterthan the second predicted time, continuously executing the firstautomatic-focusing processing, and detecting the focused lens positionof the focus lens based on the first automatic-focusing processing. 14.The image capture device according to claim 13, wherein the secondautomatic-focus control means includes means for, when the fourthdetermining means determines that the first predicted time is longerthan the second predicted time, executing the second automatic-focusingprocessing from the beginning, and detecting the focused lens positionof the focus lens based on the second automatic-focusing processing. 15.The image capture device according to claim 1, comprising: thirddetermining means for, when the second determining means determines thatthe shutter button is fully pressed, determining whether or not thefirst automatic-focusing processing is executed by the firstautomatic-focus control means, and wherein the second automatic-focuscontrol means includes means for, when the third determining meansdetermines that the first automatic-focusing processing is executed,executing the second automatic-focusing processing from the beginning,and detecting the focused lens position of the focus lens based on thesecond automatic-focusing processing.
 16. The image capture deviceaccording to claim 1, further comprising: fifth determining-means for,when the first determining means determines that the shutter button ishalf pressed, determining whether or not a half pressing operation ofthe shutter button is continued for a predetermined time or longer, andwherein the first automatic-focus control means controls theautomatic-focusing means to execute the first automatic-focusingprocessing, when the fifth determining means determines that the halfpressing operation is continued for a predetermined time or longer. 17.An image capture device comprising: capturing means for capturing asubject image; automatic exposure means for setting an appropriateexposure value for the capturing means; a shutter button which is ableto be half pressed and fully pressed; first determining means fordetermining whether or not the shutter button is half pressed; seconddetermining means for determining whether or not the shutter button isfully pressed; first automatic-exposure control means for, when thefirst determining means determines that the shutter button is halfpressed, controlling the automatic exposure means to execute a firstautomatic-exposure processing; and second automatic-exposure controlmeans for, when the second determining means determines that the shutterbutton is fully pressed, controlling the automatic exposure means toexecute a second automatic-exposure processing which is simpler than thefirst automatic-exposure processing.
 18. The image capture deviceaccording to claim 17, further comprising: third determining means for,when the second determining means determines that the shutter button isfully pressed, determining whether or not the first automatic-exposureprocessing is executed by the first automatic-exposure control means,and wherein the second automatic-exposure control means includes meansfor, when the third determining means determines that the firstautomatic-exposure processing is executed, omitting a part of the firstautomatic-exposure processing.
 19. The image capture device according toclaim 17, further comprising: fourth determining means for, when thefirst determining means determines that the shutter button is halfpressed, determining whether or not a half pressing operation of theshutter button is continued for a predetermined time or longer, andwherein the first automatic-exposure control means controls theautomatic exposure means to execute the first automatic-exposureprocessing when the fourth determining means determines that the halfpressing operation is continued for a predetermined time or longer. 20.An image capture device, comprising capturing means for capturing asubject image; automatic white balance means for setting an appropriatewhite balance value for the capturing means; a shutter button which isable to be half pressed and fully pressed; first determining means fordetermining whether or not the shutter button is half pressed; seconddetermining means for determining whether or not the shutter button isfully pressed; first automatic white balance control means for, when thefirst determining means determines that the shutter button is halfpressed, controlling the automatic white balance means to execute afirst automatic white balance processing; and second automatic whitebalance control means for, when the second determining means determinesthat the shutter button is fully pressed, controlling the automaticwhite balance means to execute a second automatic white balanceprocessing which is simpler than the first automatic white balanceprocessing.
 21. An image capture device comprising capturing means forcapturing a subject image; stroboscopic light charging means forexecuting stroboscopic light charging for a stroboscopic-light unit;stroboscopic light-emitting means for emitting a stroboscopic light byusing the stroboscopic-light unit charged by the stroboscopic lightcharging means; a shutter button; first determining means fordetermining whether or not the shutter button is operated; and capturingcontrol means for, when the first determining means determines that theshutter button is operated, controlling the capturing means to executecapturing regardless of whether or not a stroboscopic light charging isexecuted by the stroboscopic light charging means.
 22. The image capturedevice according to claim 21, wherein the capturing control meansincludes: second determining means for, when the first determining meansdetermines that the shutter button is operated, determining whether ornot stroboscopic light charging is executed by the stroboscopic lightcharging means; and stopping means for, when the second determiningmeans determines that stroboscopic light charging is executed, stoppinga stroboscopic light charging by the stroboscopic light charging means.23. The image capture device according to claim 21, wherein thecapturing control means includes means for, when the first determiningmeans determines that the shutter button is operated, controlling thecapturing means to execute capturing, and controlling the stroboscopiclight-emitting means to execute stroboscopic light-emitting.
 24. Theimage capture device according to claim 21, wherein the capturingcontrol means includes: second determining means for, when the firstdetermining means determines that the shutter button is operated,determining whether or not stroboscopic light charging is executed bythe stroboscopic light charging means; and inhibiting means for, whenthe second determining means determines that stroboscopic light chargingis executed, controlling the capturing means to execute capturing, andinhibiting stroboscopic light-emitting by the stroboscopiclight-emitting means.
 25. An image capture device comprising: capturingmeans for capturing a subject image; automatic exposure means forsetting an appropriate exposure value for the capturing means; a shutterbutton; first determining means for determining whether or not theshutter button is operated; and capturing control means for, when thefirst determining means determines that the shutter button is operated,controlling the capturing means to execute capturing regardless ofwhether or not automatic-exposure processing is executed by theautomatic exposure means.
 26. The image capture device according toclaim 25, wherein the capturing control means includes means for, whenthe first determining means determines that the shutter button isoperated, controlling the capturing means to execute capturing afterautomatic-exposure processing by the automatic exposure means isstopped.
 27. The image capture device according to claim 26, wherein thecapturing control means includes second determining means for, when thedetermining means determines that the shutter button is operated,determining whether or not automatic-exposure processing is executed bythe automatic exposure means, and the capturing control means, when thesecond determining means determined that automatic-exposure processingis executed, controls the capturing means to execute capturing afterautomatic-exposure processing is stopped.
 28. The image capture deviceaccording to claim 25, wherein the shutter button is able to be halfpressed and fully pressed; the first determining means includes: thirddetermining means for determining whether or not the shutter button ishalf pressed; fourth determining means for determining whether or notthe shutter button is fully pressed; and automatic-exposure controlmeans for, when the third determining means determines that the shutterbutton is half pressed, controlling the automatic exposure means toexecute automatic-exposure processing, and the capturing control meansincludes means for, when the fourth determining means determines thatthe shutter button is fully pressed, controlling the capturing means toexecute capturing, regardless of whether or not automatic-exposureprocessing is executed by the automatic-exposure control means.
 29. Animage capture device comprising: capturing means for capturing a subjectimage; automatic white balance means for setting an appropriate whitebalance value for the capturing means; a shutter button; firstdetermining means for determining whether or not the shutter button isoperated; and capturing control means for, when the first determiningmeans determines that the shutter button is operated, controlling thecapturing means to execute capturing, regardless of whether or notautomatic white balance processing is executed by the automatic whitebalance means.
 30. An image capture method comprising: determiningwhether or not a shutter button, which is able to be half pressed andfully pressed, is fully pressed; and executing a secondautomatic-focusing processing when it is determined that the shutterbutton is fully pressed, a processing speed of the secondautomatic-focusing processing being faster than a processing speed of afirst automatic-focusing processing which is to be executed when it isdetermined that the shutter button is half pressed.
 31. An article ofmanufacture comprising a computer usable medium having computer readableprogram code means embodied therein, the computer readable program codemeans comprising: computer readable program code means for causing acomputer to determine whether or not a shutter button, which is able tobe half pressed and fully pressed, is half pressed; computer readableprogram code means for causing a computer to determine whether or notthe shutter button is fully pressed; computer readable program codemeans for causing a computer to execute a first automatic-focusingprocessing when it is determined that the shutter button is halfpressed; computer readable program code means for causing a computer toexecute a second automatic-focusing processing when it is determinedthat the shutter button is fully pressed, a processing speed of thesecond automatic-focusing processing being faster than a processingspeed of the first automatic-focusing processing.